I have spent time on Maui, Oahu, Kauai and Hawaii (the big island). As is the case with redwitch, Maui is my favorite island. I took a cruise once which visited several of the islands and was enjoyable. If I recall correctly it was on Norwegian Cruise Line and in order to visit a foreign port we went to Kiribati
http://en.wikipedia.org/wiki/Tabuaeran (Fanning Island) which took a couple of days at sea each way.
You may want to find a timeshare or other rental if you decide to stay on Maui or Hawaii. That way you can buy groceries and eat some meals at home. Restaurant meals are expensive in the islands. Maui has a Costco not far from the airport. On Hawaii you may run into vog
Big Island Vog Index and hear coqui frogs at night.
Tiny coqui frog becomes a big problem in Hawaii - LA Times I once took a helicopter tour while in Kauai which was well worth the price. Visiting the lava flow on Hawaii where it flows across the highway is a unique experience. Visiting a coffee plantation might also be fun.