Stayed at the Double Tree in Sand Pedro and got the parking package so we could leave our car there for the 15-day trip. Well worth it since the car was safe and it's $18/day to park at the port anyway. Ended up being about a $90 room on the water when you take in the parking cost.
Next time we'll go to Kona. Volcanoes National Park wasn't as cool as I thought it would be and our tour booked through hawaiicruiseexcursions.com took us to a bunch of gift shops instead of places to see/learn.
Nothing to do but shop, felt safer on the ship and didn't want to see beggars
Board earlier than advertised, carry the bare minimum, but questionable items you don't want to haggle with the crew about (power strips especially). We would have bought an oceanview and then waited to get the balcony upgrade offer to get a better room at a decent price. It was difficult for me to keep good water on hand so the soda package was awesome and convenient since there are bars everywhere, but you had to go to deck 14 to get water. Some clubs had water, but would run out quickly.
Bought a tour through hawaiicruiseexcursions.com and our tour guide was ok, but most of the stops were gift shops and the volcano was a little underwhelming. Check YouTube for all your stops first to make sure they are interesting enough to purchase