Jekyll Island (09J) is the best Georgia coastal destination for small airplanes.
Jekyll was purchased in 1947 by the state of Georgia. Its essentially a state park. The state has limited the construction on the island keeping large portions of the island natural. They recently updated their shopping district, convention center and hotels. They have golf, putt putt, horseback riding, 22miles of amazingly scenic bike trails, a historic district and a sea turtle center.
And the best part is the hospitality of the FBO. Richard, a retired airline pilot, manages the airport. He rents out bikes and electric golf carts (Red Bug Motors). If you fly in to the island, he provides pilots limited use of the bikes and golf carts for no charge. He also runs Red Bug pizza nearby with great food. I almost always eat there. If you like Mexican food, Tortuga Jack's is a good option with the best view sitting under the Tiki hut.
The beaches are flat and hard packed sand suitable for riding bikes. At the North end of the island there is drift wood beech. The drift wood there consists of the whole tree. A very unique and beautiful place.
The ocean water around the island is murky. You can stand in 6 inches of water and not see your feet. So, I would could not recommend snorkeling.
July and August can be very hot. Would recommend going spring or fall.
A good place to fuel up is Baxley (BHC) and HazelHust,(AZE) just Northeast of Jekyll.
Note; If you go to Savannah, I would recommend the riverboat dinner cruise. Its approximately $200 for 2 and all the food you can eat. A little pricey but a good trip.