Not sure which island(s) you’re going to, but I’d make Pearl Harbor a priority of course, as well as seeing the different sand color beaches, Mount Kilauea, and other non tour guided destinations were my favorites. My favorite things to see usually aren’t the ones that have become commercialized tourist events. I’m most interested in the historical, rural, local, and military parts. The history of the islands is something I find fascinating.
Try to see the quasi-rural areas, the North shore, the huge waves, eat pineapple that are so good that they almost don’t even seem like the same fruit we can get on the mainland.
As for wildlife, Keep an eye out for the sea turtles. I was on the side of a road in Maui where the water was calm and saw a sea turtle. Then I started looking around, and it was almost like I was seeing turtles in a Southern farm pond because there were so many. I will never forget that experience. If you’re able, go snorkeling or at least swimming with goggles. The reef life and variety of fishes is worth seeing, they’re beautiful, but be careful because the ocean currents can burn you out if you’re not used to that sort of thing. Watch for the invasive mongoose, they were quite common. They look like mink.
One warning: If you get a rental car there or anywhere really, carefully inspect the vehicle before you leave. We got stuck for something that we probably weren’t responsible for causing but on the hook for due to the fine print. Had we not been flying out so soon, we should have filed a police report because while it may not have changed the fact that we were billed $1000 for something we probably didn’t damage, at least it would have been on file if that place was doing it to enough people. It absolutely had the feeling of a tourist scam, you’ve been warned.
There are roads of course. Oahu for example has a short, intrastate type road that goes from Honolulu to the other end, and there is a road that circles most the island.
