Have done the route down the coast that Mr Mcgoo describes many a time. Albeit in a heli so I get an easier pass from ATC.. See if you can get the roting though, ATC are very helpful and they hand you down from one controller to the next with a "contact x on xx freq" very helpful and v low stress.
Just make sure you wear the old lifejacket as there is a chunk of "too far to glide" between Miami and the first of the keys..
Have fun its a magical trip on a good day..