Get outdoors and skip the lines during the high season.
Utah's second-largest national park
Capitol Reef, UT
Annual attendance: 700,000
Why it's awesome: It's Utah's second-largest national park, with slot canyons, arches, cliffs, and 31 miles of well-marked trails--yet only one-fifth the number of Zion's visitors. Throw in ancient petroglyphs, a river running through a lush valley of 2,000 fruit trees, crazy geology like the 100-mile-long Waterpocket Fold, and the knockout 8-mile Scenic Drive (sans traffic).
Trail to yourself: It's a steep 2 miles up the Golden Throne Trail, but the views will do their mightiest to distract you.
OMG moment: Walking the Hickman Bridge Trail, a 133-foot-long natural stone bridge, with the Fremont River rushing nearby.
Where to pitch a tent: With a free wilderness permit from the visitor center, you can pitch a tent in the backcountry. Or choose one of the 71 shaded sites along the river at Fruita Campground ($10).
Where to book a room: Head to the funky town of Torrey, 10 miles away, for budget motels, or to the luxe Lodge at Red River Ranch in Teasdale (from $160; redriverranch.com).
More on Utah's "secret park"
North Cascades, WA
Annual attendance: Fewer than 20,000
Why it's awesome: Two peaks soar more than 9,000 feet, plus there are 312 glaciers and nearly 400 miles of hiking trails.
Trail to yourself: Worth every one of its 5.2 uphill miles, gaining 5,095 feet in elevation, Sourdough Mountain Trail is a backcountry trek to a fire watchtower that presides over 360° of awe.
OMG moment: Seeing peregrine falcons swoop, from your perch on the 389-foot-high Diablo Dam.
Where to pitch a tent: At Colonial Creek Campground ($12), you can skip stones on Diablo Lake, just outside your tent.
Where to book a room: The new lakeside Base Camp (from $95/person; ncascades.org), at the North Cascades Institute's environmental learning center, offers gourmet organic fare and nature programs.
Why camp when you can glamp? Read up on how to camp in style.
Kootenay, southeast B.C.
Where is it? The park is 200 miles north of Sandpoint, Idaho, and about two hours from Calgary International Airport. The trailhead for the Stanley Glacier Trail, featured here, is off Highway 93 in the park, 10 minutes south of better-known Banff.
Where to pitch a tent: In a subalpine spruce forest, 61 sites at Marble Canyon Campground (from $22 U.S.) are a five-minute drive from the trailhead.
Where to book a room: Your best bet for bed, bath--and hot tub--is in Banff. The Fairmont Chateau Lake Louise (from $408 U.S.; fairmont.com) is the luxe--and large--option. Kootenay Park Lodge log cabins (from $132 U.S.; kootenayparklodge.com) are an intimate, affordable alternative, as is the Banff Boutique Inn (from $205 U.S.; banffboutiqueinn.com).
Great Basin, NV
Annual attendance: 90,000
Why it's awesome: California's Sequoia and Kings Canyon National Parks have giant trees, but this park has ancient ones--like 4,000-year-old Great Basin bristlecone pines. And you can drive most of the way up 13,065-foot Wheeler Peak for extraterrestrial views of northeastern Nevada and Utah.
Trail to yourself: Lexington Arch Trail zigzags 3.4 miles to an amazing six-story limestone arch.
OMG moment: The bristlecone pines, especially when they glow in the morning sun on their namesake trail.
Where to pitch a tent: At 10,000 feet, you'll feel the altitude, but the vistas at Wheeler Peak Campground ($12) are worth a minor headache.
Where to book a room: The options are slim in the gateway town of Baker. Whispering Elms Motel (from $57; greatbasinmotel.com) is adequate. Rustic Hidden Canyon Ranch B&B (from $139; 775/234-7172) lies on 380 acres outside the park.
More on Great Basin National Park
Grand Canyon, AZ
Mule rides from the South Rim book up months in advance--and cancellations are as rare as a room with a canyon view. Instead, go to the North Rim, 215 miles away. It sees a third of the visitors and has plenty of mules for hire. Arrive at the trail rides desk in the Grand Canyon Lodge when it opens at 7, and you may find yourself in the saddle, loping in the early-morning light down the vertiginous Kaibab Trail ($75 half-day; canyonrides.com).
Grand Canyon 101
Crater Lake, OR
Rather than tailgate from viewing spot to viewing spot, park your car in the Rim Village lot and hike the moderate 6-mile (one-way) West Rim Trail, which fortunately isn't packed in the summer.
Northwest camping adventures
Since only shuttle buses are allowed on Zion Canyon Scenic Drive through October, check out Kolob Canyons. This lesser-known paradise in Zion's northwest corner (about 25 miles north on U.S. 15 from the Zion turnoff at Toquerville) remains open to private vehicles. Chug up Kolob Canyons Road, which snakes between sandstone cliffs and gains 1,000 feet of elevation in 5 miles. From the summit, hike the Timber Creek Overlook Trail, a moderate 1-mile round-trip with an eagle's perspective of Kolob's finger canyons--each a mini Zion.