Sadly there was an ongoing eruption when me and my SO visited the Big Island, so the entire park was closed. Was a bit bummed out, on the other hand people lost their homes so keeping it in perspective.

That said, I second visiting the Big Island and visit various sites. Driving less than an hour and going from barren volcanic landscapes to lush rainforests was something else, and watching the sunset from Mauna Kea was magical. And lots of great beaches, and most that weren't next to a resort had very few people.

While the island is big relative to the other Hawaiian islands, its small enough that you can drive around it in a day.

I'd recommend staying on the Kona side, which is the dry and somewhat barren side. The Hilo side has rainforests for a reason.

What struck me about the big island is that it has 8 of the 13 climate zones, and you can go around the perimeter of the island in about 5 hours.

I loved going up Mauna Kea visitor center and stargazing. At ~11,000 feet, it's one of the best places in the world for naked eye stargazing. You're literally above the clouds, the island has strict rules about exterior lights at night to minimize light pollution, and you're above the thickest air. I wasn't expecting to see the Milky Way so easily.

https://en.wikipedia.org/wiki/Milky_Way#/media/File:Milky_Wa...

The Big Island has good B&B's in many parts of the island so I recommend staying in multiple places, to see the local sights without a long drive afterwards.

A university professor here visits many areas. He complained by far the most of the dust in the air that stuck around for quite a while there.