I did this trip in Oci 1998 on the Crown Princess, Tahiti to Hawaii. If you can afford it a balcony would be great, I'd go at least for an outside. Views on both ends can be fantastic.
My weather was perfect, sunny with no wind and calm seas. Barely felt any movemnet the whole trip, not sure if that is normal. Bora Bora and Moorea are fantastic. I did 4 days precruise on Moorea then took the ferry back over to Papeete to pick up the ship.
I would sure recommend time on Moorea post cruise if at all possible, much more scenic than Tahiti itself. Flights are very limited back to the US mainland though.
Funny how I always think of this as my "Tahiti" trip and forget about the time in Hawaii. This is almost just as nice, and I'm one of those that also loved the stop at Christmas Island. Doing this on the Dawn would be even better than the Crown, more dining entertainment options onboard.
If you can book this cruise, you won't forget it!