The trail #477 is well marked and it leads across the creek on a log bridge and continues through the open forest for a short distance before starting to climb uphill. The trail enters an interesting forested area where there is a jumble of downed trees. The survey map suggests this was the result of avalanche activity, but it almost looked like a blow down. Hike on up through the debris and begin a fairly steep ascent uphill.
Above the jumbled mass of fallen trees, the trail crosses yet another stream – this one draining Cuba Gulch, on a solidly built bridge over a very narrow and deep gorge. Above the gorge, the trail switchbacks up the hillside and then follows well above the stream, still entrenched in a spectacular gorge. Continue hiking on the easy trail for almost an hour (1.9 miles) until you come to a crossing of a nameless stream that is split into two flows. There is an excellent campsite here that could accommodate multiple tents. The unnamed stream drains the basin you are heading for. It lies SW of Half Peak. Note that while the old USGS map seems to indicate the Cuba Gulch trail crosses the creek a couple times, we found that it always stays on the same (east) side. Cross the split stream and locate the trail that heads south, up the unnamed drainage to a pass on the west side of your intended summit, between it and UN12,990. This trail shows on Trails Illustrated #141 as FS #916. It is not all that well-maintained if any. While these following coordinates are not field obtained, they may help locate within about 50 yards where this trail is: N 37° 51' 49.73" W 107° 29' 30.98". Elevation 11,470 ft. The same trail continues on to the North Fork of Pole Creek.
As the map indicates, the trail climbs steeply at first through trees and on switchbacks before turning on up the drainage. Before entering the drainage, it crosses a ridge. Aim for these coordinates at 11,900 ft.: N 37° 51' 40.01 W 107° 29' 21.20". As the trees thin out, it enters an extensive area of willows where we eventually lost it for a while before finding it again as the willows thinned out. After crossing the ridge, if you don't find it immediately, aim for these coordinates - just a short distance from crossing the ridge: N 37° 51' 39.21" W 107° 29' 19.70". Continue hiking up the valley and somewhere around the 12,000 foot level, begin to veer off and head more directly toward your summit.
As we headed up out of the willows, we spotted a group of cow elk and their calves grazing further up on the slopes of the peak. Because of a small, concealing, rise we were able to get fairly close before being detected, but eventually, they ran by heading over to the pass where the trail goes. This is prime elk habitat and the willows are laced with their trails which contribute to the route finding difficulties getting through them. The north face of the peak presents a substantial cliff with a few breaks. It is now closer to veer to the west side of the peak so we walked that way, heading toward a well-used sheep trail that was marked with large rock cairns built up several feet that the shepherds have made. On the USGS map this is identified as the "East Fork Middle Pole Trail." It connects with and is a part of the CD/Colorado Trail. We intersected and followed the trail a little before continuing on uphill and heading around the cliffs to the west side of the peak. On the back (south) side, ascend easily through some rocky outcrops to a tundra and rock bench area just below the rocky summit.
The summit is capped by a large shepherd-built cairn with Half Peak as a backdrop. The view of Half is impressive and dominates the landscape. For the trip off the summit, we decided to head down the southwest ridge a little before entering a couloir that dropped through the cliffs to the NW. We found some interesting flowers to photograph as we descended and the building storm clouds to the north over the mountains made some nice photos. At the bottom of the couloir, we headed back down the easy tundra slopes and picked up the trail we had followed in the morning. This time we were able to follow more of it into the willows, but still lost it briefly before picking it back up again. The trick is that at one point, it actually goes uphill a little shortly before the descent back down into Cuba Gulch. It's also easy to lose the trail going back down into Cuba Gulch. Do not veer too far to the left (SW).
Bonus Points: UN 12,990 lies just west of UN 13,164 and is an easy, almost all tundra ascent to a Top Ten highest twelver. Makes little sense to pass this one up and will add at the most an hour to your hiking day.
Links to other information, routes & trip reports for this peak that may be helpful.