If you don't mind being a little bit north of the Keys but within day trip range, Valencia Grand in Boynton Beach is a great option to consider.

Valencia Grand offers truly premium 55+ living unlike anywhere else, with a prime South Florida location, sophisticated country-club lifestyle, and all-new unmatched amenities. Valencia Grand takes sophisticated living to the next level with one-story home designs made for 55+ living with stand-out features including expansive high ceilings, transom windows that let in even more Florida sunshine, impressive gourmet kitchens, spa-like baths, spacious outdoor living areas and more.