Since you are going that way, I'll give you a little more info.
For groceries and other supplies, you have two easy places to stop.
If you only need a Super Walmart, you can stop at Newport, TN exit 435 and head south about 1/2 mile. Usually cheap fuel here too and not too bad to get in with a trailer.
If you need more, there is a Walmart and Sam Club along with a few
other small strip mall stores at Hendersonville, NC exit 49 and head about 3/4 mile north. Turn left where you see the dedicated turn lane and Chic-falet. Walmart is down a bit and Sam's is hidden beyond them, don't see it until almost on it.
You may already know, but for those that don't, in Townsend there is an IGA about 1/3 mile to the right of the Tee. They also usually have some pretty cheap fuel.
Make sure you stop in at the Little River Railroad and Lumber Museum a little further up the road. Even if they aren't open, some of the outdoor displays are very nice. We stopped when they were closed but I want to go back when they are open.
Have fun. It'll be another couple of months before I get back up that way and can hardly wait to visit Cades Cove again.
Edit: Can you post a link for the Airstream event? My daughter's FIL has an old airstream he is finishing restoring. Since he only lives about 30 miles down Hwy 11, he may be interested in at least running up for the day.
2015 Ram 3500 4x4 Crew Cab SRW 6.4 Hemi LB 3.73 (12.4 hand calc avg mpg after 92,000 miles with camper)
2004 Lance 815 (prev: 2004 FW 35'; 1994 TT 30'; Tents)