We've covered so much of what to see and do in Hawaii, that there's not much left to say. I can say that there are tons of things to do and so many ways to do it. Your best option is to go on the state's website and view, download, or order the information that they supply to start. There are so many things that you may want to just book a tour with a company and cut out all the planning and let someone else do it.
Hawaii is one of the most desirable vacation destinations in the world. It is also one of the most desirable places in the world to live. Let me put some cautions out there. Prices are high. Whatever you do will cost you. There was a time when people were having yurts designed because they couldn't afford to buy a house. Everything that is not made or grown on the island has to be imported. There is no way to drive to another state or country; you must fly or take a long ride on a ship. Don't let the Interstate Highways fool you.
Hawaii is beautiful, but remember, it is isolated as much as a place really can be in this day and age. It comes with dangers, just like Iceland in volcanoes. It comes with dangers just like the Caribbean in hurricanes/typhoons. There are landslides in heavy rain. It isn't always paradise, so you may want to pick your season.
And remember, this place has been plagued by Covid-19 just like everywhere else. There may be rules for entry, and there may be rules for public activity. Always check before you go.
Something else that a lot of people aren't used to. Everything has a price. Cruises and trips to Disney tend to be inclusive. In Hawaii festivals can be expensive, plantation tours are expensive, boats are expensive, luaus are expensive, food and gifts are expensive as is lodging. If you want to take a helicopter tour, go deep sea fishing, diving or anything of the sort, you will pay. This is just another reason why I say; check guided tours for the whole vacation. It's much better in a place like Hawaii to know what your paying and have it booked before you go. I like to wander, but unless you travel with someone who lives there, plan ahead on this trip.
With all the cautions being out there now, what can I say? Hawaii is one of the most amazing places on Earth, so go for it. Ride in a submarine, swim with sharks, ride in an outrigger, learn to surf. Eat some Spam, visit Pearl Harbor, take a cruise, visit a crater, visit a volcano. Fish, sunbathe, buy a Hawaiian shirt, take a drive, take a flight, take a boat, look at waterfalls. There's so much to do that it took me several entries to cover it, and I'm sure I missed a lot. So, do your homework, I hope that the links I provide will help, and Enjoy!