GETTING THERE: Haleakala National Park is in the crater of the dormant volcano atop Maui's highest mountain. It's about a two-hour drive from Kahului or 21/2 hours from the resorts on the coast. The road ascends 10,000 feet over its 37-mile length, so count on slow-going switchbacks and ears popping. You can drive your own car (park admission is $10), and if you arrive after 10 a.m., you'll find space in the summit parking lots. If you prefer to let somebody else do the driving, bus tours of Haleakala (888-909-0010, www.alohatopten.com) start at about $45.
ENJOYING THE PARK: Haleakala is beautiful all day, not just at sunrise and sunset. The Kalahaku Overlook (at Mile Marker 19) is an excellent place to see rare Hawaiian silverswords, the round, spikey ferns. You may also encounter the nene, an endangered Hawaiian goose familiar to crossword puzzle solvers. Nearly 30 miles of trails, ranging from half-mile jaunts to all-day treks, welcome hikers of all ability levels. Horseback riding is another popular activity.
BIKING DOWN THE MOUNTAIN: Downhill bike trips come in several varieties: sunrise or mid-morning, self-paced or guided. Self-paced trips, such as those offered by Haleakala Bike Company (808-575-9575, www.bikemaui.com), drop you at the summit and, after escorting you to the park exit, let you wander downhill, stopping where you like for food, water and photo breaks. Price starts at about $80. Guided tours, like the ones available from Maui Downhill (800-535-2453, www.mauidownhill.com), provide an escort all the way down and stop at predetermined places along the way. They range in price from about $80 to $150; some include a park tour.
Almost all companies provide bikes, helmets and foul-weather gear. Many will also take non-cycling passengers to and from the park at significantly lower rates than for bikers.
TIPS: No matter when you go, dress in layers. You may be in T-shirt and shorts in the middle of the day and a parka and gloves at sunrise or sunset . . . If you're planning to visit for sunrise, go on the first day of your trip. It will be easier to wake up early when you're still jet-lagged . . . Remember that for a sunrise, you'll drive up the mountain in complete darkness and, in the busiest seasons, have to fight hundreds of other visitors for a parking spot. At sunset, the park is much less crowded, but you'll drive down the winding road in twilight.
INFO: Check with Haleakala National Park (808-572-4400, www.nps.gov/hale) for sunrise and sunset times. The Maui Visitors Bureau (800-525-6284, www.visitmaui.com) can help you find accommodations.
-- John Rosenthal