I do not see a grass airstrip, so I question your claim.Little Saint James island (also commonly known as Epstein island) has a grass strip (that's an airport, Wally).
More importantly, landing a Boeing 727-100 on a grass airstrip is a crash landing. It is not meant to be landed on grass. It would not be able to take off. It weighs between 40 and 80 tons.
So we know that people did not fly to Epstein's Island on Epstein's Boeing 727-100, because his plane is not crashed on the island.
A sea landing of a Boeing 727-100 is even worse.Both islands also use seaplane bases (that's an airport, Wally).