County doesn't matter as much as finding a neighborhood where most people are in your same
life stage.
I'd go for walks in a chosen neighborhood and see who's around, to ask about how long most homeowners have been there. If most have been there 15 years or more and you're about to be newly retired, I'd avoid that because because I'd want to be with neighbors who are prone to active living and being out and about, able to be sociable.
I'd also check the tax appraiser records of a particular neighborhood and street, to see how many of the houses have sold in the last couple of years. Some have not had "new blood" in quite awhile.
Sumter County Property Appraiser
Met a lively just-retired couple the other night who just retired and moved somewhere in Ashland area (fairly new, in the middle of TV). The woman said they regret that they're surrounded by almost all elderly widows who can't do things, and so there's no social activity in their neighborhood. And before jumping on me...we love the several widows in our neighborhood....they are happy and on the go and involved in everything that goes on in the neighborhood and elsewhere.