DO: Drive to Hana - don't take a tour bus. Allow 12 hours+. You'll need a very early start. Weather permitting drive all the way around the island, don't turn back at Oheo Glutch. (Ignore your rental car contract. Check the bulletin board at Oheo Gultch for road conditions). Or, spend a night in Hana and make it a 2 day trip.

DO: Use sunscreen. I've seen more lobster-red miserable tourists than you can imagine. You really will burn much faster in Hawaii than other places.

Enjoy your trip!