Kelly Flats has long been the premier hard-core trail in northern Colorado. The trail climbs steeply out of the Cache La Poudre River Valley and winds for a considerable distance across a high ridge with beautiful views of the Mummy Range on a clear day. Noted obstacles include The Chutes and Heart Attack Hill. A wet spring often delays May 15 opening of the trail, so call ahead to verify. ATVs and UTVs may find this trail too difficult.