I don't know much about the upper part of the state but this is what I can tell you about the bottom third. There are only a couple of places you can camp on Cumberland Island (CI). Brickhill is at the North end of CI. Sea Camp is at the southern end of CI (about a half mile away from where you take out at). These are on the inland side of CI. The campsites on the ocean side are probably too far to walk to and you would either have to leave your boat on the beach or carry a portage cart with you. CI is a National Park and requires fees & reservations to camp. For more information on CI go to http://www.nps.gov/cuis/index.htm
I would stay at Brickhill then paddle down to Tiger Island which is just south of CI (about two miles past the sea Camp landing) which is a free, first come - first serve campsite. http://www.dep.state.fl.us/gwt/paddling/Segments/Segment%2026/Segment26.htm
Map of Tiger Island location & GPS info. http://www.dep.state.fl.us/gwt/paddling/Segments/Segment%2026/PDF/Seg26map2.pdf
This is from the website.
"You have the option of camping under live oaks at a primitive site on Little Tiger Island, which is managed by Fort Clinch State Park, or you can camp at the park itself. The safest way to reach Little Tiger Island is to cross the Amelia River at the county boat ramp and hug the sandy western shore until reaching Tiger Creek. Proceed west about a quarter mile up Tiger Creek and the Little Tiger Island campsite will be on your right (see map for GPS point). No reservations are necessary for camping at Little Tiger Island at this time. Campers should adhere to Leave No Trace principles. Fort Clinch is directly east of Tiger Island, but do not attempt to cross this wide expanse of water unless conditions are calm.
You can camp at one of two campgrounds at Fort Clinch State Park. However, water access is highly restricted in the park. The park will allow for kayaks to land at the River Campground about a half mile before the fort, but you may have to carry your kayaks to your campsite. Sites 29, 30, 39, 40, 41 and 43 are near the water. Reservations are recommended. If you are registered at the campground without a vehicle and seeking to launch the next day, the park will ask you to wade and pull your boat along the shore about 1,000 feet south to the county-operated North End Boat Ramp. This is due to strong currents and liability concerns."
Pull-Up Strap Handle Kit