so much info, so little time.
The SW fla area is packed with GREAT cruising. The Burnt Store Marina has several chartering services, also Fishermans Village in Punta Gorda. As for the time of year, I'd say November or April/May. The mid-winter times are tough down here. The wind is high (15-20) and the waters become quite shallow in a NE wind direction. It might not be too cold for you being from the north but for us it is cold. The Gulf of Mexico can be an angry piece of water when the winds are from the N to NW. The summer is terribly hot and humid. If that doesn't bother you than maybe the mosquitoes (swamp angels)and no-see-ums will. As for the thunderstorms, watch out, they'll hurt you. From Charlotte Harbor area you can be in Key West in 48 hours. There is soooo much great sailing and places to see in the Charlotte Harbor area (Boca Grande, Punta Gorda down to Ft Myers, Pine Island Sound, etc, etc,) that leaving the SW coast area would be a shame. Good luck and enjoy your time, the Charlotte Harbor area is beautiful, I live here and I still love sailing and cruising this area.