Hey CBill I don't have a boat but chartered out of st Pete in October. I was on a 37 ft Beneteau and sailed in Tampa Bay the 1st day and anchored at Desoto Pt the first night. On the second day we goofed off in the gulf and stayed at Long Boat Key anchored for the night. The 3rd day we hit the gulf again and sailed to Venice and anchored behind the marina for the night. That's as far south we went and returned back to St Pete in reverse order.
Desoto Pt was very beautiful and peaceful. Long boat key was ok but had a ton of dolphins everywhere and they were constantly putting on a show for us. Oh and you could anchor right behind this nice restaurant and eat if you wanted. We really liked Venice with all the big beautiful homes and loved everyone taking our pictures when we motored into the inlet. There were a lot of people fishing and hanging out at the entrance to Venice. Now the people at the marina and the convenience store weren't very friendly but we didn't really care, we got our beer and ice, so it was all good.
The only advice I can give you is WATCH your depths! Lots of shoals everywhere and make sure your charts are up to date and bring a camera.lol.