I think you'll find Trailriders Wall in late spring looks more like this. I did it in early May a few years back in a similar low-snow year. It was certainly doable, but I'm not sure I'd recommend it too highly. Above 9,500' or so, it was a slog of postholing through rotten snowdrifts, and I lost the trail, despite having done the hike a couple times. But there was clear ground for camping around PB Lake, plenty of clear walking above treeline, and I saw lots of bighorns.