I'd recommend stopping at Jekyll Island instead of Sea Island. Just over the bridge onto Jekyll you take a left to go to the Jekyll Island Club Hotel which is a former winter home to the likes of the Firestone's, Vanderbilt's, etc. Beautiful property and historic. There's a sea turtle rescue hospital on property you can tour. While there, walk down to the pier and have lunch at Latitude 31 for a real seafood treat. Often times you'll see shrimp boats unloading fresh caught shrimp right into the restaurant!