I get asked at times about retirement and where to retire, what surprised me, what I do with my time, etc.
My first comment is "Go where things encourage you to walk."  If you like golf or tennis, whatever, do it, move where it's easier to do.  I pretty much gave up golf many years ago.  I just saw my clubs yesterday in the storage room covered in dust and thought about going to the range.
I can still run and lift a bit, which is great, but if all I could manage was walking I'd feel lucky.  I'm not 80 (yet).