This trail can be accessed from Ousel Falls Trail with parking area and signage just west of Big Sky town center. Yellow Mule Trail leaves the Ousel Falls Trail just before the falls, and crosses a paved road where the climbing begins.
It's a public right-of-way through logging areas to Forest Service land, ultimately climbing through extensive subalpine meadows and the ATV trail at the top of Buck Ridge. Like most Forest Service trails around Big Sky, it's old-school mountain biking, with steep grades, rutted track and some unrideable climbs, but the views are worth the effort. This is probably a better descent, if you make the climb up Second Yellow Mule #42 instead.