I've never had a problem getting into Harborside. Our favorite time is May, after the Easter/Spring break crowd, but before hurricane season. It's tough to get St John, but we learned it is frequently better to call later (2 months out) rather than early (8 months out) because they have some cancellations from people who booked early and couldn't keep their plans. I would avoid both places during peak hurricane season, mid August to end of September. Not that you will be caught in a hurricane, but you will have nearly daily thunderstorms and a lot of rain in the late afternoon. It's very hot and humid during that time of year. We prefer May or November for more moderate weather and warmer temperatures without the winter winds and cold fronts that you get from December thru February. We went to St John in December, and the air and water were warm, but the "Christmas Winds", as they refer to them, made the water so rough that they closed many of the favorite beaches to swimming, including the snorkel area at Trunk Bay. The boats don't go out during the windy season, and it's not worth it to go all the way to St John just to sit at the pool. I see you're from Sarasota- you know what these cold fronts do to the surf this time of year. The temps aren't affected as much in St John, but they sure are in the Bahamas. Plus, I'm sure you're used to tracking the hurricanes of late summer and know how these areas have had so many close calls over the last few years - much more so than Florida.