Be sure to fill up your gas tank before you leave for Hana. There are no gas stations on the way there, but then again it is only 30 miles or so. We did not have a full tank of gas and did not fill up in Hana and made it back to our condo on empty!! The road to Hana is only 30 miles long and you can't really go that far past Hana before it turns into a dirt road anyway.
A long but very scenic road along the north shore to Hana. As there are so many rainbows you can see in Maui, within the three hours are all kinds of weather conditions.