Do a luau. On Maui, the big one in Lahaina is very good. On Oahu, if the cultural center is stlil in operation, I've read that it is one of the best "old style" ones.

Snorkel on Maui and Kauai, if you're able. Maui is probably the better bet for a whale tour, and you'll be there at a good time for it. If you do a sunrise at Haleakala, you may have to call to get a reservation for it, and bring something warm to wear. Road to Hana on Maui, and keep on driving past Hana and hit the gravel road that circles back around. Look for Pat Benatar in Hana. Go to Pearl and the north shore while on Oahu; you can take The Bus to both, I believe. Lots to see and do, and you'll love it. Hope the Corona stuff is down by then and no mandatory visitor quarantine by then.