When To Go: Summer is the most popular time to visit, but that's when temperatures beyond the dunes can occasionally reach 100 (nights, however, cool down considerably because of the altitude). Spring and autumn are enjoyable but the weather can be changeable. During winter expect cold days and nights (sometimes below zero) and periodic snow. The monument is open year round, although during the winter months both close-in accommodations are closed.
The monument -- the visitors center is just inside the only entrance. Open daily; summer, 8 a.m. to 6 p.m., winter, 8 a.m. to 4:30 p.m. It contains exhibits, books, brochures, maps, wilderness permits (which are free), and schedules of activities such as hikes and campfire programs. (719) 378-2312; Internet, www.nps.gov/grsa. Entrance fee: $3 for those over 17, children free. Trails: No trails in the dunes, walk where you want. Ten park trails go into the grasslands, the pinion-juniper woodlands and the ponderosa forests. The 4WD Medano Pass Primitive Road begins in the park and goes north to Medano Pass.
Accommodations -- the monument has one developed campground with 88 sites, all on a first-come, first-served basis; $10 per site, up to six people per site. Three group sites are available, to handle 15 to 40 people; $3 per individual; reservations recommended. Backcountry camping (wilderness permit required) is allowed at designated sites and in the dunes. Open fires and gathering wood are prohibited; firewood is sold in the park for campground use. Dune campers are asked to do so two ridgetops back from the main front and to follow the leave-no-trace philosophy.
Two accommodations border the monument: Great Sand Dunes Oasis is open from about April 1 through Nov. 1 and offers a campground ($10 for the first two adults, each additional $2.50), RV pull ups ($16.50 for first two adults, each additional $2.50), basic cabins with no services ($30 a night), and lodge rooms ($70 to $80). Reservations recommended. (719) 378-2222. The Inn at Zapata Ranch is a restored ranch with 15 rooms ($150 to $225) and is open from the end of March to the end of October. Reservations recommended. (719) 378-2356.
Beyond that, conventional motels and restaurants can be found 38 miles to the southwest in Alamosa.