Near enough to Orlando on the Atlantic side you can go to Outdoor Resorts Melbourne Beach or North Beach Campground north of St-Augustine Beach - both have a pool(s) and are across the street from the beach.
On the Gulf side, the only one I know is RedCoconut that's already been mentioned but there's no pool and while a lot of people like it, it's really packed tight there and quite expensive so I wouldn't go.
I believe there are some in the Panhandle but offhand I don't know which ones. When are you planning your trip (I would only go to the Panhandle from May-Oct otherwise I think the water is too cold for my taste)