Renting the SUV was a perfect choice and enabled us to enjoy the whole island! The memory foam pads were extremely comfortable for sleeping with the hatch open (get a bug net) or when we needed to use the tent. We slept best in the car. Roosters are plentiful and noisy. We didn't need it but the 4-wheel drive was a comforting option. Double-check your gear before setting off. A quick trip to Walmart for food, reef-safe sunscreen, liquor, and ice is a good call. A sun umbrella could come in handy, too.
Finding campsites was very challenging! Camp Olowalu was great, but not private at all. We called the phone numbers listed and learned it is best to go in person because none answered or responded. State parks charge $50 per person per night and were all booked! Fishing overnight for one night on some beaches is tolerated we were told. Rooftop tents just got outlawed as well, so be extra considerate and find secure spots only. Adds to the trip cost but we would not do it any other way!