I live on Sanibel Island, we are clear of the airspace from RSW and FMY. There are a couple of heliports near so see and avoid. Be aware of low flying sight seeing aircraft and banner towing aircraft. They are frequently below 500 feet. My biggest concern is the mosquito control helicopters, they will appear out of nowhere and routinely fly at 75 feet above ground level. They do not post NOTAMS and show up frequently.
I consider Ding Darling NWR a No Fly Zone, don't even think about flying your drone while inside the boundaries of the National Wildlife Refuge. You will be quickly escorted out, and most likely never see your Mavic again. There are a couple of areas you can fly from to get shots of the NWR without actually flying over it. Contact me privately if you want that info. All in all Sanibel is drone friendly, you can fly from any public land or private land you have permission from. Pilots are requested to stay 2000 feet above National Wildlife Refuges.
Besides the Gulf of Mexico Views there are a lot of cool walking and bicycle trails.