Me three. And unless you go to Oahu, it's usually a four leg trip to and from another island.

If you really want to go to another island, however, a suggestion would be a trip to Pearl Harbor. My nephew and his wife took a day trip to do this just to see the Arizona Memorial. However, they were on Kauai for two weeks and went, not because they were bored, but it was something they really wanted to do.