Peter
I was down there two winters ago, when they were experiencing record cold temperatures. The folks, especially Ken, at The Angling Company, located at 333 Simonton Street was very helpful.
Your plan to drive back I think is a good one. While I didn't fish them, there were some state parks just north of Key West that has good access. Seems to me that I read somewhere these are good places for the "self guided" fly fisher to check out.
Dave
" If a man is truly blessed, he returns home from fishing to the best catch of his life." Christopher Armour