Nashville?

I've visited it a couple of times, it's not bad, a typical Southern city, quite segregated, not as racist as some places though: the amenities seemed decent, and it appears not too expensive to live, but public transport is (as usual) derisory.

Immigrating to the US for retired people is moderately tough, as you won't get in on an H1B visa, and I dont think there's another longstay visa you'd be eligible for - unless you can bring in at least $500,000 and start/buy a small business?

You can apply for the green card lottery each year & the odds aren't terrible: you could also come in on a tourist visa, then simply overstay it forever - so long as you don't want any government support of any sort, you are very unlikely to be noticed or anything done about it.

On the other hand, all medical care is on the basis of paid health insurance. Unless you've been working here for a number of years, you wont be eligible for Medicare (free health insurance for the elderly), so any medical care is likely to be hideously expensive (and if you're retired, there's going to be medical expenses, of course).