Utah

The area's spectacular hoodoos—towering spires of eroded limestone—have a strange, otherworldly beauty that's fascinating for both children and adults. Walk among the formations, which reach up to 150 feet, along the easy Mossy Cave Trail or Rim Trail (the latter has flat stretches of toddler-friendly hiking). Stop at Bryce Point and Inspiration Point to admire the canyon's rocks, which fade from red to gold to violet as the sun arcs overhead. At the 1920s-era Bryce Canyon Lodge, stay in one of the 40 individual cabins, which have spacious double rooms and wood-burning fireplaces, and are quieter than the units in the main lodge.
Bryce Canyon Lodge, open April to October; from $140 a night for a double; (888) 297-2757.

Rangers will lead families or small groups on educational walks along the sandstone cliffs and narrow canyons of this 229-square-mile park. Don't miss the 2,000-foot Weeping Rock, where rainwater that percolates through the porous red sandstone on top has created a hanging garden of wildflowers. The Pa'rus Trail is a car-free paved road that's great for families with strollers or beginning bicyclists. Although the park's ranch-style Zion Lodge (originally built in the 1920s and rebuilt after a 1966 fire) doesn't have the majestic presence of some other lodges, it does feel quaint and authentic. Each of the 40 cabins has its own stone fireplace and private porch or balcony—ask for a westward-facing one, which will have the best view.
Zion Lodge, from $151 a night for a double, (888) 297-2757.

Washington

Depending on the time of year, you can spend your days at this Cascade Range park snowshoeing and making snowballs or exploring the subalpine meadows along one of the 260 miles of trails. Gaze at Mount Rainier (still an active volcano) from the Paradise Inn, where you can tuck in after dark. Evenings can be spent with tea and cookies before one of the stone-hearth fireplaces, or sampling the local fare (try the buffalo stew) in the dining room, which features massive beams of Alaskan cedar. The inn is closed for renovation until May 2008, but visitors should make reservations well in advance once it begins accepting them again later this year.
Paradise Inn, open May to October; from $105 a night for a double with no private bath; (360) 569-2275.

Wyoming

The craggy Tetons are incredible to look at but tough to climb. There are, however, many easy walks—even for small kids—that offer views of the range, including the two-mile Colter Bay Nature Trail, which skirts a forested peninsula into Jackson Lake. After hiking, spend an afternoon fishing in the lake or rafting along the Snake River. (If you catch a fish, the lodge's chef will cook it up for your dinner.) With a swimming pool, spacious cabins, and porches with big views (ask for a mountainside unit), the Jackson Lake Lodge is perfect for families.
Jackson Lake Lodge, open May to September; from $189 a night for a double; (307) 543-3100.