The daily pilgrimage to the House of the Sun (Haleakala) begins creepy early, people leave Lahaina and Kihei at the crack of 3 a.m. in order to drive to the pavilion at Red Hill Summit to catch the sunrise. You freeze your butt off. Often enough, cloud cover or storms cancel the show.
Try leaving a little later when you can see the summit. And bring your big-boy hiking gear for a trek down Sliding Sands Trail into the vast crater (which technically is a eroded valley). It's easy to be sucked in by the beauty and hike father than you want into the hinterlands of Haleakala. The homeward leg can be a ball-buster. The trailhead is at 10,000 feet.
To really enjoy the moods of the volcano, and see a night sky that's a jewel box on black velvet, try renting one of three rustic cabins availalble from the National Park Service. People plan way in advance for these cabins, but you can often snag one at the last minute. We've hiked in with just daypacks with bedding in garbage bags.
Another way to take full measure of this otherworldly land on pink cinder cones is to ride a horse. Several stables offer day trips. You'll see all you would on a two or three day pack trip. Maui Trailblazer has details on visiting Haleakala, including a couple of trails that are off the tourist track and totally awesome (like the Skyline Trail).