We're doing the whole of Hawaii, Im planning on a decent amount of island hopping. Apparently they dont have a ferry that goes from island to island, but since I am GM (and therefore god) there will be such a service.
Heleakala has already been brought up, and I've got a beautiful picture of it to use in the game. Also, Im thinking there is going to be a rather large drug problem, since that seems to be a real life issue in the Hawaiian Islands. Im also thinking there is going to be allot of Faerie influence here, since weather is a big deal in hawaii.