There are a few simple things you should do before you begin the drive that will eliminate a lot of hassle. Fill up the car in Pa’ia, that seems obvious, but there are no gas stations between Pa’ia and Hana and you never know what could happen. The same goes for food, stop by Hana Picnic Co. for a picnic lunch and snacks for the road because you are at the mercy of roadside fruit stands until you reach Hana,  there are no fast food pit stops. It is also probably wise to determine beforehand which stops have restroom facilities, especially if you are traveling with children.