If you take out certain areas of west TN, the crime rate becomes lowest in the country.
Exactly. "State" crime rates are wholly irrelevant to a potential retireee. Same for "access to medical care" on the state level. If you like the general aspects of a state(ie, weather, tax rates, retiree friendly policies etc), then all you need do is pick a location within that state that does NOT have a high crime rate and has decent access to medical care.
Using Tennessee as an example. Yeah, if you retire to Memphis, you're getting a dose of all the bad. But after that, you have dozens of solid choices if you happen to like the other aspects of Tennessee.
BUT, if a state has oppressive tax rates and less than friendly policies towards retirees, there are ZERO cities you can choose to avoid this problem.