Yukin Peak / the Coffee Cat Shuffle is spectacular trail running route. The entire route is on hiking trails that range from mellow at the start and end of the out-and-back route, to vertiginous in places as you traverse the eroding slope above the glacier and navigate around mountaineers with massive backpacks and cargo-horse convoys heading to and from Camp 1. Mind-blowing glaciated peaks and multicolored mountains fill your view the entire route.
I ran the route solo and unsupported, carrying two-liters of water and a handful of snickers bars. Luckily, conditions were great, with cool temps, and glacier breeze and damp terrain that improved grip. I only needed a liter of water and one snickers. The last kilometer to the peak is absolute crux, with an average gradient of about 30% combined with the thin air. But the scree descent is super fun (provided that hikers above you aren't kicking loose rocks!)
One significant deviation from the route posted by Meredith last August is that there is no longer a natural glacier bridge over the river on the approach to Camp 1. Therefore it is necessary to continue on the slope on the right side of the river (on the approach) and traverse the river at the point where horsemen wait to ferry trekkers and mountaineers across. The river ranged from calf deep on the approach to thigh deep on the return - it can become impassable on hot days. The deviation probably makes the route a bit easier than last year given the trail on the glacier was sketchy and rocky, whereas the trail on the slope is mostly runnable. The tradeoff was wet feet and shoes full of little rocks and silt.