My wife and I were in Mountain City last Saturday for a craft show and really enjoyed it. And I am quite familiar with all the other places you mentioned.
My take on the Mountain City area is that peole there friendly, but they seemed to have a larged influx of people from other states moving in, but all communities in the Tennessee Valley and the Appalachian Mountains are experiencing this. I can't really speak to the Cumberland plateau area, but I have no doubt that it's experiencing the same thing.
While in Mountain City, I talked to one couple that just retired and moved up here from Texas. They bought their house via the internet and didn't see it until they actually moved in. But they love it and he has already cut a couple of ricks of firewood for the coming winter. I also met another Texan and another couple from California that had moved up there, as well as a couple that had moved back from Wilkes County, NC, to take care of her ailing father. All had moved this year. I suspect that prices there are being driven up, by new people that are moving into the area.
I think the same thing is going on in the Johnson City, Irwin Area and the Sweetwater area. The Knoxville, restate market is RED HOT right now. I mean SURFACE OF THE SUN HOT! Houses here are sold within a day or two of going on the market, regardless of the price. Went to an estate sale yesterday. The house was well over 3,000 sq ft and north of $600K and they inked the deal four days after going on the market. I have a friend that has lost out on 6 houses in the last three weeks, because people are paying way over asking price. Apartments are extremely hard to get here too. As are new manufactured homes.
I guess the gist of this is that regardless of where you go, it's not going to be cheap. Make sure you squeeze every last dime out of your home in Florida. You might very well need it here. Even for a Barbie Doll Playhouse!!!