Cumberland Gap itself was interesting, and I'd like to go back sometime.
I visited several states with mask requirements while traveling the past few days, and it really wasn't that big of a deal. It doesn't affect you at all while on the road or outdoors, and grabbing a mask for indoor public places has become habit by now. It would have been a bigger shock to visit somewhere and find that it wasn't required at this point.
I've been there many times, and unless I'm pressed for time and needing to get where I'm going, or in a hurry to get home, I always drive down into the town to see if the "TENN-US 25E" sign is still there, and how it's holding up.
I've driven all the major routes in the area (both 25s, 27, 23/26, both 11s, both 19s, 321, 421, various state routes linking county seats, the new TN 91 bypass of downtown Mountain City, and have been to Morristown since the ramp and overpass were built at the shopping area along 25E. I'm not sure if there's anything particularly scenic or roadgeeky I may have missed.
I wouldn't mind staying in Kentucky, but I can't think of anything that's new since the last time I was in a particular area beyond US 68 reconstruction between Millersburg and Carlisle. When you've run out of things to explore without having to drive 2-4 hours just to get there, it takes some of the fun out of it.