I certainly remembered you and the tips you gave us before our cruise. We had a wonderful time and the only problem now is that we can't seem to come back to earth! Both of us spend time each day remembering the wonderful experiences we had in Hawaii and on the ship.
The bus ride to Lahaina was the star tip of our excursions. As I mentioned, we hooked up with another couple from the ship so I felt responsible (and slightly under pressure) to get us there. Actually, meeting them was a kinda cute thing. We were having quite a late dinner our first night on board and there were just a few people in the restaurant. By no means were we eavesdropping, but we overheard this couple asking a waiter for directions to Lahaina as they were going to the Old Lahaina Luau. Because I had looked into this extensively, I knew that his answer was totally wrong and would not get them there. When he left, I went over to them and offered the benefit of my research and said I would give them a copy of the bus schedule. They asked if they could just tag along with us and we were friends from that moment! Although the luau was the only excursion that we did together, we spent many hours relaxing on board with them and are now in e-mail contact.
The bus leaves from the somewhat vast Queen Kaahumanu Mall - I believe it was on the West side on the building. Getting there was also a longer walk from the dock that we thought and it was really hot that day! There is a shuttle bus that will take you from the dock to this mall but it is expensive for what it is and we thought we could walk there in a few minutes. We made it just in time for the 2:30 bus which gave us about an hour and a half in Lahaina. This place is a must! I later found out that NCL offers itineraries that dock off the coast at Lahaina. My tip would be to go for that one. I would have like to explore the rest of the West coast up to the resorts but of course, there wasn't time for that. Next time!
I think you may have misunderstood my message about car hire and doing excursions on your own. Certainly a trip to the Volcanoes National Park on the Big Island should be escorted - for one thing the guide will tell you what to look out for and remember, this place is actively volcanic and dangerous in places. A hike round the Waimea Canyon in Kauai would be excellent but again, unless you are a very experienced hiker, it could be dangerous. The helicopter flight was not at all scary and an excellent thing to do. I would recommend booking directly with one of the helicopter companies which would probably give you more time in the air. I felt that we had too much of a schedule to stick to on our flight booked through NCL.
I went into a bit more detail here than you may have needed, but I like to give fuller descriptions of things for others who may be interested in doing one of these trips.