The NCL ships that sit in Hawaii don't have to hit a foreign port. They are all three U.S. flagged vessels. You fly to Honolulu and catch the ship, it does 7 nights around the islands and ends in Honolulu, you fly home. If you're wanting a west coast sailing to Hawaii Princess and Celeb have ships that do 14 and 15 day itineraries and hit a foreign port.
If you're looking for a ship with a reputation for very good food and service you're going to be taking a 2 week trip from the west coast. If you're looking for a great value and maximum time at the islands fly in a do a week with NCL. The nicest ship, as of next year would be Pride of America. Pride of Hawaii is being moved and Pride of Aloha is starting to show her age from reports I get, maybe they'll refurb it before you go.
Hope this helps, Neil