There are few drives as harrowing as the one back from Hana. If it has been raining you can expect washouts and there are generally unpaved stretches and these are pretty bumpy.
But, the stark back side of Haleakela is striking, and there are a couple of beaches full of rocks...a photographers field day!
The ride around West Maui is more challenging. There are sections where you must wait for oncoming traffic. Many vehicles turned around at this point. And the rental companies will not come to get you if there is a problem.
All in all , it is an experience that I will not soon forget but I'll rent a four wheel drive next time.More