Hi Lumley! Welcome to the board! There are quite a few of us from the Fort Myers/Naples area...
My wife and just bought a boat, are working on it, and hope to have it up and running soon so we can start diving more locally vs. driving to sites, however, there are lots of sites that us locals in the area hit. Unfortunately there arent really any in the immediate vicinity of the counties (i.e. beaches or lake) that I know of.. I've tried local shore dives, which are pretty cool from a marine ecology perspective, but not everyones bag of tea.
Most everyone I know in our area travels to Venice or Ft Lauderdale to shore dive if they dont have a boat. Keep an eye on the board, we always seem to be meeting up somewhere.