How about a loop on its own island? Well, feels like an island, anyway. Rockaway Hunting Club on Long Island, holes 7-14, where you tee off across a channel on the par-4 7th, cross a rickety bridge to get to the fairway, then play three holes along the water, turn inland a little, and then at the par-3 14th play a long shot diagonally across the channel again and then recross that same bridge to get to the green.