Yes, I agree with the previous posts about staying in Hawaii pre- and post-cruise. The cruise part is wonderful, and it's a very relaxing way to get from island to island while you sleep, and you have the added bonus of being at sea, which I love. We stayed in Honolulu for 1 day precruise (it was also a stop on the itinerary that sailed 7-day roundtrip from Maui) and Maui 3 days postcruise, and that was a great trip.
Just my opinion, but I don't think a lot of NCL at all. We have cruised all over the world (going to South America this year), and I've been on NCL 3 times and do not think it compares favorably with Royal Caribbean, Princess, etc. I think you could do better than NCL.