So you are aware if you are in the Smokies you are technically required to camp in the designated campsites or shelters if you're going to follow the AT or be in the backcountry. If Rangers catch you without a permit it can come with a hefty fine. The permits are free and you can get them something like 30 days before heading out, check out the goods here: Backcountry Camping - Backpacking - Great Smoky Mountains National Park
. Car camping happens in the "frontcountry" if that's more your style.
Things that would help would be how much backcountry experience you have, and if you hike regularly. There are some pretty mellow loops and there are some loops with some good gain. I guess the next question would be how long are you hoping to be in the backcountry?
It's been a while since I've been back to the motherland, but I pretty much grew up in GSMNP.