We did Celebrity's Infinity departing Honolulu April 18. We flew over to Honolulu 3 days early and saw Oahu on our own, then boarded the ship and cruised the islands. I'm not sure what we liked the most: the islands ..... or the ship!
After cruising the islands, the ship sailed 4-days back to Ensenada, Mexico. We were fortunate to have a cabin with a verandah and only had 1 day when it was really too cool to have the door open or to actually use the verandah.
We were bused from Ensenada up to San Diego and flew home from there. We liked this route rather than the reverse, which is sailing from Ensenada to the islands and departing from Honolulu back home.
We really enjoyed this cruise. WHile you don't get to really see everything on each of the islands, this cruise, like the Medit. cruises, gives you a chance to get a good overview.
We were able to see much of each of the islands because we rented a car and did not do shore excursions through the cruise line. Would strongly recommend doing this - doesn't take long to drive the "circle" around most of the islands.
Enjoy Hawaii - what ever you decide to do.