Trip trading/dropping is not easy right now, can't rely on it to make your schedule work. You will need some kind of crashpad on Oahu if you live on the Big Island and are junior interisland. The earliest flights leave Honolulu around 5 am and the last flights arrive after 11 pm. You could try Aloha freighters to travel outside those times. but I'm not sure how reliable that would be. Most of the widebody trips leave between noon and five and arrive around the same time making commuting easier.