Clothes: I would definitely bring some light synthetic long underwear -- top and bottom. Your sleeping bag is on the edge for May in the Smokies, and you'll likely need the long johns to sleep in. I would bring a pair of wool sleeping socks, too, and keep all my sleeping gear *dry*. (I keep my sleep clothes in a gallon ziploc bag inside my sleeping bag stuff sack, which is a roll-top dry-bag type silnylon bag. Double protection for the clothes.)

For hiking, a pair of Columbia nylon shorts with a mesh liner will be fine, especially if you already have rain pants that you can wear in camp over your long johns. You can get nice synthetic t-shirts at Target in the men's athletic department, both short and long sleeve, for pretty cheap. I'd buy a short sleeve to hike in and a long sleeve as my camp/sleeping/backup shirt. (If you want to hike in pants, you can get Columbia zip-off pants on sale in many sporting goods stores. You'll need synthetic underwear to go with them, or go commando. REI also has some nice zip-offs made of very light nylon.) You'll want a second pair of the Smartwool socks.

Boots: take them back to the outfitter and see if a pair of Superfeet insoles helps with the fit.

Cookware: the K-Mart Grease Pot is a good cheap option. Also, you can get some great cookware from www.antigravitygear.com. You'll need a Lexan spoon, and a small folding knife.

Shelter: the tent is great. You don't need a footprint.

Water Treatment: I use Aqua Mira. It's easy to use and pretty cheap (about $13 for a set.) Follow the directions on the bottle, and make sure you drink enough.

The Hike: Do NOT discount that 3000 foot climb on the first day. That is a significant climb for a first hike. I don't think it's too ambitious, though, unless you are driving all day and hope to knock out that climb after a 3pm start. Just take it very easy on the climb, take a 10-15 minute break every hour (or more as needed), and make sure you drink enough water. Dehydration will sap your energy before you can react.