Longs Peak via the Keyhole Route: The only fourteener in Rocky Mountain National Park, Longs Peak (14,259 feet) requires some preparation — and plenty of nerve. Not only do you have to start hiking the 15-mile (round-trip) route, which rises some 5,000 feet in elevation, around 3 a.m., but it requires Class 3 rock scrambling.

Boulder Skyline Traverse: It’ll take most of the day to bag the five major peaks overlooking the People’s Republic. The 16.5-mile (one-way) trail doesn’t demand special equipment or ability, but you will need solid navigation skills to safely cover the 12,000 feet in elevation gain. Also, you must shuttle a vehicle so you have a way home.

Stratton Reservoir: Closer to home, the hike to Stratton Reservoir in North Cheyenne Cañon Park stretches 14 miles (out and back) and 4,000 vertical feet. The stats aren’t the most difficult part, though: The route is largely unmarked and requires some bushwhacking so should only be attempted by experienced hikers and navigators.

DALIAH SINGER, SPECIAL TO THE GAZETTE