I suggest renting a vehicle at the airport - cheaper than other places. That'll give you the chance to drive around and see the island. Be careful of the North Coast, because it can be extremely crowded during surfing season. But there are some amazing roadside shrimp restaurants up there that are awesome! They have their own shrimp ponds in the back, so your shrimp were alive 5 minutes before you eat them. Can't get any fresher than that!!
You can also pre-book reservations at Pearl Harbor, which is a must for those of us who are ex-Navy.
Travel Agent/Cruise Specialist w/13 yrs exp and 48 Cruises on 11 cruise lines! Favorites: Paul Gauguin - Tahiti: Uniworld River Cruises - Europe; Celebrity Solstice-class ships; Holland America - 12-nights Baltics & Russia; RCCL - 14-nights Greek Isles, Turkey, & Croatia; Holland America - 14-day Alaskan cruisetour; 10-night Canada/New England cruise; 21 days Hawaii w/7-night NCL cruise; Oceania - 25 days in Asia; more than 3 months touring Europe by train. And many all-inclusive resorts!