We went to Hawaii for two weeks in late September/early October. I recommend two week vacations especially if you are tripping across multiple time zones. We went to Maui, Hawaii and Kauai. We took a helicopter ride on Kauai and now I want a helicopter. I have no idea where we will put it, how much it will cost, or even how to fly it. No matter.
Holei Sea Arch on the Big Island.
We drove the road to Hana and it was harrowing. I do not know why that trip is a recommended trip. After being terrified of one lane bridges on hair-pin turns and assholes not paying a lick of attention, you end up here which is pretty but not worth it.
Also, Lahaina is heart-breaking.
Kauai is magnificently beautiful. I recommend. This is Spouting Horn.