As in Aug, Sept, Oct- fla keys

[silver suz]

I'm looking for a good place to camp in Aug, Sept, Oct on the Fla keys especially in walking distance of good-excellent snorkeling, spots. I need 50 amps for my 31' 1977 AS soverign. Would prefer a park with plenty of space in between , on the beach, dont care about pools, amenities except for a food store within walking distance. 50 amps and snorkeling are the most important!
Unable to drive, so once I'm there I'm there ,until someone takes me home. does anyone know of such places? I'm an expert snorkeler with equipment. Therefore interested in fantastic coral and fish and no beginner groups! I identify fish and coral species like birders do with a life list. Any such place exist- with fresh air and clean water?
silver suz