The drive up to view the sunrise from the summit of the Haleakala Crater is long, and has to be completed early in the morning.  The road is in very good shape, with guard rails most of the way, but it is winding and at that time of the morning it is very dark.  Take your time and look for places to move over for faster moving vehicles behind you.  Try to arrive early to avoid fighting the crowds, and give yourself time to enjoy the incredible landscape even after the sun has come up.  It can be very cold at the summit (approximately 10,000' above sea level) compared to the rest of the island so dress appropriately.  In addition to the cooler temperatures, the elevation can be a problem for a lot of people.  Don't over exert yourself, and if you feel faint take a long break before doing anything.  The drive can be long, the road somewhat treacherous, but the view at sunrise is unforgettable.

Even better, you do not have to drive up at sunrise, but instead you can hike into the crater itself. There are two trails in, one a relatively gentle switchback and the other called Sliding Sands (for a reason.) Either trail is an amazing experience to descend into another world. The island of Manhattan can fit inside the crater which has it's own weather.

You can hike out the same day but even better is to camp or best yet, reserve a cabin at the bottom of the crater. There are three cabins available and you can hike from one to another. The last cabin is on the East side of Maui and is lush compared to the lunar landscape of the others. A rare once in a lifetime experience.