This is an easy half-mile hike (one way) along South Boulder Creek. It's a lovely trail runs along the creek with small waterfalls and up to a small cave.
This trail is labeled "moderately difficult". It climbs 1.4 miles up 600 feet to the remains of the Crags hotel which burned down in 1913. On the way are great views! The trail continues as a .8 mile loop (up another 600 feet) to a view of the Continental Divide. The roundtrip distance about 3.6 miles.