A great deal depends on which month you will begin. A February start will mean LOTS of insulation. Even an April start will require more than you might think. The Smokies, owing to sheer elevation above 5000 feet, have a climate akin to the Vermont coast.
So, consider down for camp use in February and March, especially if you intend to use shelters more than your tent/tarp. However, remember that LOTS of moisture is common, so it would also be worth considering a high-loft synthetic such as Primaloft for a jacket. BPL's Cocoon series is an excellent ultralight option for such clothing and others exist from a number of manufacturers.
Also consider posting this question on Whiteblaze.net. Don't be surprized if the answers eventually have nothing to do with your post, but the first dozen or so post will likely hold good info. I would also recommend posting early on a weekday morning. Otherwise your post gets lost in the sheer volume of other posts and nobody sees it.
Best of luck.