Need advise on an ultra light sleep system

I am new to this and have spent some money on decent gear. I ended up buying an REI dash 2 tent that only weights 2.5 lbs, cat can stove, Thermarest zlite pad. REI flash 62 pack that weights 2 lbs. My issue is my sleeping bag ( marmot trestle 1 which weighs about 4 lbs and barely fits in the bottom uf my pack compressed. I am trying not to spend a lot more money on gear right now. Dueter makes a sleeping back called the dreamlite 500. I think its rating is between 50 degree. Most of my trips will be no lower than 40 with an extreme of 35 degrees. I was wondering if I could buy that bag. Its like 80 dollars and then buy a SOL escape bivy to put the bag inside. With a total weight of 1.5 lbs or should I weight and just buy a down bag later

My preference is always down. It is the lightest and most compressible of all fill materials so far. I have found decent ones used. Keep watching! If you can acquire a Costco down blanket, consider making a lightweight sleeping quilt. I'm reading a lot of good buzz about this blanket and items made from such as DIY gear.

I have too, CM, and I wish I could get my hands on a few cheap. At least one store was reported to have them on clearance for $10. But, I neither live anywhere close to a Costco (it's not an online item) nor do I have a membership. If this is an option for the OP, however, I'd love to hear how it goes. Hammockforums.net has a lot of info in the DIY section about optimizing these for camping, including easily resizing them without having to open them up and mess with down and getting the most loft out of them. If one isn't warm enough, you can double up.

+1

No Costco membership for me, either. If my sister gets here to visit Mom before I go home, I'm hoping she will bring one (or two) or we can get some here.

Hammockhangers.net also has some DIY discussion about using these.

Down for me, too. However, it's a bit pricey for those on a budget. The Western Mountaineering Ultralite that I bought in 2006 for $315 is, last time I looked, edging close to $500. At some point, it's going to become cheaper to raise your own geese! If you have the money, though, a high quality down bag is worth the price. Properly cared for, it will last a lifetime, while synthetic bags tend to loose a significant amount of loft after 5-6 years. The cost per year of useful life is definitely less, assuming you have the $$$ up front!

Sleeping bags with lower quality down are, of course, heavier than the expensive ones, but not nearly as heavy or as bulky as your synthetic. Check out the Kelty Cosmic Down. Properly cared for, it will last far longer than your synthetic bag. It's often on sale, so check numerous vendors.

A quilt is another possibility. I am not a quilt person, but many experienced people here swear by quilts from Enlightened Equipment. I suspect they don't toss and turn as much as I do.

Don't forget that a sleeping pad is a very important part of your sleeping system. The ground is often colder than the air. Even more important, the part of the sleeping bag that's under you gets squashed flat while you're in it, so has far less insulation.

It would help to know where and at what times of year you backpack.

check this out. 1lb 5oz. http://www.gofastandlight.com/Rip-Stop-Nylon-Summer-Season-Sleeping-Bag/productinfo/S-WFS-XLITE/

You might consider extending your range with a woobie. Google military poncho liner or woobie. I've used one and they are as described and also can be found for under 30 bucks. Great piece of gear under 1.5 lbs.

That looks pretty nice. How warm are they? Could you rate it around 50 degrees?

You'd need to wear some clothes to sleep, but , yes, I think that'd be a safe lower limit. It's about what I did. I also wore a buff around my ears for just a little more warmth. They are easy to throw over you if you're sitting around camp, too. Note: I was in a tent, and my tent is good at blocking wind and is considered a "warm" tent. I was also on an inflatable pad rated R3.2 .

have you ever looked at the army patrol bags? They are 2 pounds. They only thing that concerns me is compression.

They end up as a fairly small package when used with a compression sack, and look pretty good for the price you can buy them for. I must admit, once it drops under 50, I have high end down bags that do a great job for little weight/space penalties.
I watched a you tube of a patrol bag in use. I was shown the 4 part system by a military friend, but haven't used it. Used with a woobie, I would guess under 40 is getting possible. Not bad for a cheap modular, relatively lightweight sleep system. Before my good friend that is very involved in logistics/supply took his full time commission and started doing his equipment testing in Afghanistan and Iraq, he owned a backpacking store in Vt. (My wholesale priced toy store!) We often laugh about the difference in philosophy between outdoor companies and the military. The military could care less about comfort. Being kept alive is all the comfort a soldier needs. We're going to do a trip together early this summer, til then I won't see one in use up close.