Having done this cruise just last year, I can definitely say it's an amazing cruise. Food on the ship was not that great, but the staff was wonderful. And save yourself ALOT of money by pre-reserving rental cars in each port. You can do your own thing in your own time, see more, do more, and not have to worry about the crowds. I wrote a complete cruise review but can't post it in this forum as it only allows about 2000 words and mine is much longer than that. If you're interested in reading it, let me know via PM and I'll send it to you. It's got alot of great information.
If you can, you'll want to spend at least a couple of days prior to your cruise in Honolulu. It'll not only give you some time to decompress after a long trip, but it'll also afford you the opportunity to see the sights. You can also rent a car at the airport very cheaply, but unfortunately parking is pricey unless your hotel offers a good package.
And if you're planning to go to Pearl Harbor, make sure you get there early. They open at 7:30am, but there will most likely already be a long line. The tickets are free, but they are time-stamped and even if you get there at 8:00am, you can end up waiting 3 hours or more and if you don't get there before 10:00am or 11:00am, you may not get any tickets because the last program begins at 3:00pm.