I can't steer you to a Hawaii discussion board, but you may ask me as many questions as you want!
I've lived here (on Oahu) my entire life (32 years). I've visited the Big Island many times, Maui 3 times, and I went to Kauai for a day trip once just this past October. The only thing I probably won't be much help with is telling you how to find good discounts. In Hawaii, we have "kamaaina" (or locals) discounts, that don't apply to others.