We've done quite a few of these excursions before. I like the idea of the scooters Karen, even though I've never ridden one before. We will likely do this with you and Mark. Due to Tom's bad back, we best not do the 4 wheel type things.
In Nuka Hiva the Tamure Welcome at Sacred Marae excursion is probably complimentary to the entire ship, it was on the World Cruise. There really is NOTHING else to do there that I'm aware of.
I would probably like to do the underwater walk again, it is a lot of fun if it's like BOB was. Also may rent wave runners (somewhere) but probably independently and not through RSSC.
For those who have never been to the Lagoonatarium or swam with the sting rays, these are lots of fun. The water is so warm, you can't go wrong with any of the snorkling excursions.