Northwest of Boulder in the Arapaho National Forest, the Switzerland Trail (FS327) is a 8 mile route along an old railroad grade from 7700 to 9000 feet.
To reach the Sugarloaf Mountain Trailhead of the Switzerland trail from Boulder, start at Canyon and Broadway. Head west on Canyon (SR119) for 4.8 miles towards Nederland. Shortly after passing through a tunnel, turn right heading north on Sugarloaf Road (CR122) for 5 miles. Turn right on Sugarloaf Mountain Road and continue 0.9 miles to the trailhead parking.
There are additional access points. It can be accessed from the Peak-to-Peak Highway (SR 72) at the southwest end, Fourmile Canyon at the low point from the east, or Gold Hill Road on the northeast.
Note: Colorado residents must register their off-highway vehicle with the Colorado State Parks (303) 866-3437. Out-of-state residents who bring OHVs into Colorado must purchase a Colorado Non-Resident OHV permit which is valid from the date of purchase through the following March 31. These permits can be purchased anywhere you get your hunting/fishing licenses in Colorado. All off-highway vehicles must have an approved muffler and spark arrester. These requirements are subject to change so make sure to contact the Colorado State Parks prior to using your off-highway vehicle.
Note: As of September 2007, ATV riding on Forest Service roads is only permited on roads marked as open to ATV. All ATVs must be registered.