I've had occasion to be in Sweetwater (between Knoxville and Chattanooga just off I-75) a few times in the past 2 months. Apparently this used to be a chow-free zone, but there's a few gems to find these days.
2 brand-new joints: Grillers Catfish Pub has an all-you-can eat catfish dinner for $8.95. It's whole catfish (not filets) on the smallish side, but is outstandingly fried. The fish has that perfect, fresh, earthy taste you only get in catfish in the south. You can also get chicken or chicken & catfish for the same price, but the fish was so good I never tried the chicken.
There's a new BBQ joint across the street whose name escapes me. Very good ribs, great pulled pork, lousy chicken.
Finally, southern breakfast in all its glory can be found on the buffet at the Dinner Bell restaurant. I never understood biscuits and gravy until eating here. My first visit the biscuits were transcendently airy and wonderful, the second time they were merely excellent. Country ham 2 ways (straight-up fried and in redeye gravy). Eggs, sausage (links and country patties), hash browns, potato/cheese bake, grits, everything was excellent. I ate 'til it hurt.