I don't know if this was answered but there is so much to do in Hawaii on all the islands. You can swim, surf, hike, zip line, go to historical and intesting scenic sites, kayak, or just lie on the beach. There's definitely something for everyone. Take a look at all the excursions offered and that will give you some idea. Also the website: gohawaii is really great. I looked at all of the excursions
DCL offers on each island and have saved a few to my favorites. I will do all excursions through DCL and not rent a car. I know a few ppl on the FB are renting a car on each island. I am traveling with a young child so I am limited in some ways. We will likely do some sightseeing excursions and get some beach time in.