I would assume when you head north from FL you will be taking I95. If so, Jekyll Island in GA is a really good park, plus they have FHU which is nice. The campground there is beautiful with the spanish moss. As mentioned earlier in an above post, James Island in Charleston, SC. James Island is ran by the county and is a really neat park. FHU as well. Minutes from downtown Charleston but a very secluded campground. Both Jekyll and James Island have tremendous paved bicycle trails that run the entire perimeter of the island.