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.

From the Chapin Pass trailhead ( 2) at 11,000 feet, head uphill just a few hundred yards to a right turn marked with a sign for "Chapin, Chiquita & Ypsilon Summits" ( 3). Follow the clear trail over a small drainage and gradually uphill ( 4), ( 5).

At 0.75 miles, reach a trail split with a sign pointing right to "All Summits" ( 6). Go right. Reach another trail split shortly thereafter without a sign ( 7). Go right again.

At around 1.25 miles from the trailhead, the route skirting Mt. Chapin (12,454') and ascending Mt. Chiquita (13069') comes into view ( 8). On the approach to the Chapin-Chiquita saddle at 12,000 feet, cross a trail intersection and keep going straight ( 9). Continue up on clear trail until it dissolves into class 2 rock ( 10) at around 2.5 miles and 13,000 feet. Cross the rocks to the true summit ( 11).

From Chiquita's summit, survey Ypsilon ( 1) and the route across the saddle ( 12). Head west off the Chiquita summit to access the saddle, which drops just 200 feet ( 13). Ascend across tundra on the other side of the saddle ( 14), more or less passing just inside of Ypsilon's east face. Follow cairns once it turns to Class 2 rock ( 15), climb toward the first false summit at around 13,300 ( 16), find more cairns and distinct vertical flakes of rock ( 17), and approach another false summit ( 18) just after the southern branch of the Ypsilon "Y" couloir for which the mountain was named. Pass this and find the true summit (13,514') at 4 miles from the trailhead, just beyond the northern branch of the "Y" ( 19).

The crossing to Fairchild is more difficult, but it's clearly visible ( 20) from Ypsilon's summit. Head west off Ypsilon's summit to access the easiest descent into the Ypsilon-Fairchild saddle. At around 13,050 feet, turn north and begin descending down steep and loose class 2 rocks ( 21). Stay east of the larger rocks to keep it as Class 2.

Descend 700 vertical feet to 12,350 on the saddle before beginning a northeasterly ascent up Fairchild's southern slope ( 22). Class 2 steep and loose ( 23) gradually gives way to a series of short Class 3 scrambles ( 24) for about 900 vertical feet total from the bottom of the saddle to the top of this first slope. Ascend 200 more vertical feet in a less steep series of Class 2 false summits ( 25) and reach the true summit of Fairchild at 13,502 feet ( 26), 5.7 miles from the trailhead.

Return the same way down Fairchild, dropping 1200 feet to the saddle and then climbing 700 feet back up to the ridge on Ypsilon's western slope ( 27). From here, save about a half mile and 700 vertical feet by sidehilling at 13,000 feet across Ypsilon's western slope ( 28) to the Ypsilon-Chiquita saddle. Cross the saddle and continue sidehilling across Chiquita's western slope until meeting back with the clear ascent trail.

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