We are a young couple in our early thirties, and stayed in a balcony forward room on deck 7 port side. I highly recommend a balcony for this cruise and particularly port side to best view the Napali coast. We enjoyed the ports of call, and booked the cruise for the itinerary, and to try and pack in as much of Hawaii as we could. We rented a car in Maui and Kauai and took ship tours on the Big Island.
Volcanoes National Park was a highlight and the tour guide captain Rob was excellent. Not so for the Historic Kona tour, what a waste of time stopping at a coffee shop with terribly weak drip coffees and they were out of milk so had no espresso coffees. Total waste of time. They cram too many people into the painted church at the same time as well. The only thing I really enjoyed on this tour was the Place of Refuge but we only had like half an hour there! Rent a car and drive there yourself. The luau booked through Ncl was great fun and great not to have to worry about driving with an open bar.
Driving around in Hawaii was no problem at all, up Haleakala crater in Maui was a challenging drive with lots of twists and turns, but we didn't have any trouble with rentals and driving at all. Car rental shuttles were plentiful from the ship, however book the cars ahead of time as there are not that any rentals in some ports.