Hello Britterny, I have only been to Maui and the Big island is next this coming winter. I’ve actual found a few 100% gluten free restaurants in my research (Sweet Marie’s on Kauai, Lotus Cafe on the Big island). We rented a condo that had a kitchen, so I could control my own food and keep costs down. There are Wholefoods and other health food stores, so there is access to the basic gluten free staples, the rest you can get at standard grocery stores or farmer markets. If you have any questions about Maui feel free to ask and if you find something during your research on the Big island let me know.
I was planning on going here whilst in Hawaii in May but it was closed the day I wanted to go – I was close to tears!!!
Rock and brews do a fab GF pizza though which I had (Maui)
Couldn’t find sweet Marie’s for the life of me!