1 (0=Paved, 6=Very Difficult 4WD)Old Fall River is one way. Return via Trail Ridge Road.
Chapin Pass trailhead is located on Old Fall River Road inside the Fall River Road Entrance of Rocky Mountain National Park. From Estes Park take Highway 34 to the Fall River Entrance. From the entrance follow the road just past the viewing area for bighorn sheep, with Bighorn Mountain on your right. Turn right after 2 miles in the park and head up Old Fall River Road. Travel 6.9 miles up Old Fall River Road, counting from when it turns to dirt. The trailhead has a clear sign. Park on the turn out at the left side of the road. Note that Rocky Mountain National Park has a substantial entry fee and pet restrictions.
Old Fall River Road is closed in winter. It usually opens in July. Trail Ridge Road is a few weeks sooner.