If you like swimming with sea turtles and seeing different kinds of lava then check out the big island for sure.
The vegan restaurants aren’t as plentiful as on Maui but options abound everywhere we went. The greatest part is the coffee, everywhere you go it is absolutely delicious. We traveled from Kona down to the southern most point of the USA, up to volcanoes national park over to the super vegan friendly hippie town of Pahoa in puna and then up to Hilo.
I highly recommend camping but make sure to get your permits in advance, if it’s a state park 7 days minimum a county park is less but they supposedly fill up. We didn’t see anyone at issac hale park besides George the awesome security guard. The hostel by the bay in Hilo was terrific but the hostel in volcano was my worst experience on the big island, the guy who runs it should not be in the hospitality business. The health food stores all have hot bars, the one in Pahoa was the best and we liked bong brothers too. Otherwise Thai and Vietnamese places abound, and the Hilo Farmer’s market was amazing. Down in ocean view we stayed at lova lava Eco resort where they just had a bunch of pop up VW camper vans set up among the lava field. They also had a whole fabulous cooking set up and an open air lava shower. It is the quietest place I have ever been to in the world, especially since we were the only ones there. Like a dead show after the end of the world. Highly recommended. I also recommend cooking whenever possible because the ingredients are outstanding and going out eat in Hawaii is as expensive as New York City.
Also, if the only thing to eat in the entire state was the smoothies you would still be happy as a clam. They are indescribable, my favorite was at “what’s shakin” but really they are always good.