First, your questions about fabrics. For a base layer and for underwear (if you wear it), you want a very thin, loose-weave layer of knit synthetic or merino wool next to your skin. The idea is to wick not only sweat but "insensible" moisture, which your skin produces even when you aren't sweating, away from your skin. Synthetic wicking fabrics (various kinds of knit polyester or polypropylene) are less expensive, but they tend to become pretty ripe after days of wear. Using baking soda or borax in the wash water helps to keep the stench from becoming permanent. Polypro was the standard for a long time, but recent advances in polyester make it just as wicking and have also added treatments to resist the stench. Polypro melts, or at least becomes harsh, in the clothes dryer, so polyester is better for those not careful about their laundry practices. Note that you should never use fabric softener when laundering any wicking layer because it reduces the wicking properties by partially blocking the fabric pores. Both these fabrics are extremely fast-drying, polypro more so than polyester.

Merino wool, the natural base-layer fabric, comes from a special breed of sheep, recognizable by their many deep skin folds, that produces an unusually fine and soft wool. Unlike normal wool (which I can't stand next to my skin), it feels soft, not scratchy, and doesn't itch. Merino sheep have always been around; they are an ancient European breed originally from Spain. They were never a popular breed because their many large skin folds are not practical on the western ranges (where most US sheep used to be raised) and make it harder to shear the sheep. I don't know where merino wool was used before it recently became popular for base layers and socks, but until recently I never before encountered it in hiking clothes. It's more expensive than synthetic and doesn't wear quite as well. Unlike synthetics, it does absorb some moisture, but it feels warm and dry even when damp. It also doesn't retain body odor as synthetics do. I ran a test last fall with a pair of Smartwool socks and a pair of Thorlo synthetic (mostly acrylic) socks of equal thickness. After laundering, the Smartwool socks air-dried at least an hour faster and, when still a bit damp, felt far less clammy inside than did the Thorlo socks.

The insulating layer (middle layer) requires something fluffy that traps lots of dead air (which is what really does the insulating). The most used insulating fabrics are either polyester fleece or a combination of polyester batting inside a very thin breathable nylon shell. The first is heavier and the latter is quite a bit more expensive. You can find good fleece garments in any big-box store or your local thrift store. IMHO there's no point in spending big $$$ for the very pricey fleece found in hiking/climbing stores (North Face, etc.). Just hold it up to the light to make sure there are no thin spots. Campmor's house brand fleece garments are modestly priced and excellent. Polyester fleece comes in 100-weight (light), 200-weight (medium) and 300-weight ( heavy). I haven't tried "windproof" fleece, but I'm told it's heavier and slower drying. I personally prefer a couple of lighter insulating layers to one heavy layer for more accurate regulation of body temperature. One important principle of cold-weather hiking is to avoid sweating (which soon leads to chilling), which means shedding layers when moving and adding them back when sitting still--I call it the "onion principle." Wool as an insulation layer is fine, too, but definitely heavier. Since the insulating layer is not against your bare skin, expensive merino wool isn't necessary--just your average garden-variety wool sweater. Some like a down insulating jacket, but it absorbs more sweat (you probably won't wear this layer while actually moving anyway, because you want to avoid sweating). A down jacket might be more appropriate for winter conditions since it's lighter and warmer. Since I use a down sleeping bag, I personally like to hedge my bets by using synthetic insulating clothing. In Midwest conditions in summer, I suspect that a 100-weight polyester fleece jacket is probably the most you'd need.

Many people like to use a lightweight wind shirt for windy conditions or for very light rain (i.e. fog and drizzle). This is usually made out of a thin nylon material with some kind of Durable Water Repellent (DWR) finish. There are a number of DWR treatments available to renew the finish after laundering. The cheapest version would be any lightweight, unlined, uncoated nylon jacket ("windbreaker"). The DWR fabric is water resistant, not waterproof, but far more breathable than any rain jacket. You can get away with using your rain gear as a windproof layer, and I've done this, but it's really nice to have the extra breathability. The windshirt is handy to keep the bugs off you at rest stops (when I didn't take it last summer, the flies regarded my Permethrin-sprayed base layer shirt as so much appetizer, and I got well-chewed).

The outer layer, aka rain gear, can be waterproof and breathable ("breathable" being not very, IMHO) or just waterproof and non-breathable. To me there isn't much difference--if it's warm, I sweat and "wet out" just as much inside either. You can also select between a rain jacket and pants or a poncho (with gaiters or rain chaps to protect your legs). Out here in the Pacific Northwest, we may be hiking through wet brush for hours after it has stopped raining, so leg protection is important. The most breathable rain gear I've found is Frogg Toggs, which are also cheap. Unfortunately they aren't very durable, so aren't recommended if you're bushwacking through thorns and such.

I backpack in the Cascades spring through fall, and take a trip to the Rockies in summer. Temperatures in those alpine regions can get below freezing at night, with possible light snow any month of the year (although rare in the Cascades between July 5 and the end of August, I have seen it). In other words, not the kind of conditions you encounter in the Midwest, where the definition of "cold rain" might be 55* instead of 35*. When it's hot out here, the humidity is very low. If you ever plan to journey westward for a trip to the mountains, my list may be useful, but it's overkill for Indiana.

Please note that the following clothing list satisfies my own idiosyncratic preferences in the conditions I've described. To quote our favorite saying on this board, Your Mileage May Vary!

I hike in long sleeves and long pants, even when it's hot. I burn easily and am allergic to most sunscreens, so I keep covered up instead of slathering on chemicals. Long sleeves and pants also help keep the bugs off. When it's hot out here, the humidity, fortunately, is very low. If I were hiking in Indiana summers, I would wear something cooler, such as a long-sleeved, very loose lightweight shirt, rather than the base layer top. Underarm ventilation (such as mesh inserts) would be a good thing.

Underwear: Since I'm female, nylon sports bra and panties, made with loose knit. I especially like Ex-Officio. These are opaque enough to double as a 2-piece swim suit, and they dry very fast. Whatever you use for underwear, if anything, should be a highly breathable synthetic.

Base layer: Patagonia Capilene 2 bottoms and long-sleeve zip-tee. The top is also my hiking shirt. The bottoms are worn mostly in the sleeping bag and cold evenings and mornings. I don't wear them while on the move. I also have a short-sleeve merino wool T shirt that I use for an extra mid-layer in extra cold weather and wear at night in the sleeping bag if the Capilene 2 top is wet or dirty. This may be a little more than I really need, but I like to wear relatively clean and dry clothing inside my sleeping bag. My one luxury clothing item is a pair of soft, cuddly fleece socks for sleeping--my feet sigh in gratitude when I put them on!

Hiking pants--lightweight nylon long pants or Campmor Trekmor nylon convertible pants (the latter if I'm going where streams need to be forded, when I remove the lower legs to reduce current drag).

The good thing about my hiking layer is that if it gets wet, my body heat will very soon dry it out. I found this out when I slipped and fell into a stream I was fording on a cool, damp day last summer. Once I got hiking again, everything but my boots (Goretex lined, took almost 3 days to dry) was dry in less than 20 minutes.

Hiking hat: Sunday Afternoons Adventure hat. Thoroughly shades my face, well ventilated (mesh sides and a wicking headband), fits under rainjacket hood so keeps rain off my face/glasses. I could part with any other piece of gear or use a less expensive substitute, but not this hat!

Insulating layer: Montbell UL Thermawap jacket. The equivalent of this very pricey but very lightweight jacket would be a 200-weight fleece jacket plus windshirt. Either would be too warm for a Midwestern summer but would be good for spring and fall. I normally wear this only during rest stops or around camp when it's cold. If it gets really cold I would wear it to bed at night to supplement the sleeping bag. I don't take an insulating layer for my lower body because I've found that the combination of base layer, hiking pants and rain pants are sufficient.

Wind shirt: Montbell UL. I use this when hiking in light drizzle and/or fog (unless it's really warm, when I just wear the hiking layer and get wet), when it's windy (obviously) and at rest stops to keep the bugs (especially biting flies) off my upper body. If you get Montbell (which is extremely pricey), note that their sizes run really small. I normally wear a women's medium, but with Montbell a women's large is a snug fit. There are many other brands of windshirt which weigh in the 3-4 oz. range.

Outer layer: Brawny Gear silicone-coated nylon (silnylon) top and pants, waterproof and nonbreathable. My choice is undoubtedly controversial! My experience has shown me that unless it's quite cold, I become drenched from my own sweat while hiking even in breathable rain gear. When it's warm, I'm better off using my windshirt or just letting my hiking layer get wet. Only Frogg Toggs seem to be breathable enough for me not to drown inside. When it's quite cold and wet, it doesn't matter whether the rain gear is breathable or not because then I don't sweat. When it's cold and raining, I don't wear any insulating layers under the rain jacket when I'm actually hiking, although if it is around freezing I may add the above-mentioned merino wool T-shirt or a lightweight fleece vest. A bonus is that this waterproof, non-breathable gear can be worn over my base layer in the sleeping bag as a vapor barrier on below-freezing nights. This helps keep moisture from my body from condensing (or freezing) inside the outer shell of my sleeping bag, which would wet out the down. I'd like to note that Brawny Gear (and presumably other silnylon rain gear) needs to be carefully seam-sealed, especially around the base of the hood. Test all new raingear in the shower before taking it into the field.

For head and hands, I have a lightweight fleece balaclava, a pair of polypropylene fleece liner gloves (both Manzella, bought at Campmor) and a pair of waterproof rain overmitts (Mountain Laurel Designs). Some kind of warm hat is especially important, because more body heat is lost through the head than anywhere else. ("When your feet are cold, put on a hat.") You can regulate your whole body temperature, especially while hiking, just with head and neck covering.

The only "spare" clothing I take is socks (plus the aforementioned sleeping socks). Otherwise, I don't believe in taking more clothing than I would wear all at one time in the worst conditions I might encounter--sitting around on top of a windy, above-timberline pass in a late-summer snow, not that I would willingly stop and sit around in such conditions. Some people consider their sleeping bag as part of their insulation--they hike long hours, stop to cook dinner in late afternoon before hiking a few hours more, and get into their sleeping bags right away when they've made camp. This means they can lighten up on other insulation. My hiking style is different: I like to camp relatively early, have a leisurely dinner and wander around the area admiring the sunset scenery. I therefore want to be comfortably warm without my sleeping bag. YMMV again!

Early spring with its highly variable weather conditions (in most parts of the country) is an excellent time to experiment with various clothing items to find out what works for you. You can test the effectiveness of the insulating layers you may already have and practice your temperature regulating techniques (keeping yourself in a state that is not cold but not warm enough to sweat) during dayhikes. The best place to try out camping gear and gain some experience is the back yard (yours or a friend's). It does take more resolution to force yourself to sleep outdoors in nasty weather, but you need to learn to cope with such conditions. In the back yard, if everything goes south, you can safely retreat to the warm, dry indoors to ponder what you might do differently next time. Car-camping (with your car heater close by) is another good place for learning and gear testing.

Sorry about the length of this missive; I got a bit carried away!