Here's a couple ideas a bit more south.... San Carlos RV Park in Ft. Myers. Most sites are on the water, they have plenty of dockage and a ramp - FHU,50 amp . It is pretty pricey- check their website. Fish Hurricane Bay, Matanzas Harbor and the Gulf Waters.
E.G. Simmons County park in Ruskin. Most sites are waterfront( canal) , while no docks at the sites, you can pull your boat up to shore- it's all sand. There is a good ramp/dock area in the park. Water and electric(30 amp) with a couple of dump stations. You can fish Tampa Bay, the Gulf, Little Manatee River, Cockroach Bay. I think sites are $20/nite - but they don't take reservations. Call ahead and check... with a truck camper you will have a better chance as some sites are length challenged for the larger RV's.
If you are lucky and can get a reservation, Ft. Desoto in Pinellas County has many waterfront sites and a huge ramp area. Beaches are great. Boat access to Tampa Bay and the Gulf.