Generally done clockwise as a loop (see the Rim Trail Loop
ride), this one starts off with a 700' vertical climb. The trail is well-built for bikes though, with widely-rounded switchbacks and a very smooth surface, so it's a very enjoyable climb. It's pretty exposed to the southern sun, so it could be quite hot on a warm sunny day.
Once at the top, take a left and go 100 yards to the high point and enjoy the remarkable 360 degree view.
Return those 100 yards, then continue on slightly descending, fast and fun singletrack right along the rim. There are occasional breaks in the trees that are worth stopping for and taking a peek.
More fun descending, sometimes through forest, takes you to a saddle point and a road crossing. This is a bailout option if you're in a hurry or tired. Otherwise, continue on, with some moderate climbing until you get to one final 400 climb.
Like the first climb, the surface is nice and it's well laid out for bikes, and it's over pretty fast. More great views from a bench at this high point.
Now it's a pure descent all the way to the car, and it's a blast: singletrack all the way through some aspens, but mostly sage meadows on nicely contoured trail. The views are astounding if you can take your eyes off the trail for a second. This final three quarter miles of trail (just after the final wood boardwalk / bridges) is a new trail extension constructed late summer 2014. This section is great swoopy fun, and brings you closer to the bikepath that leads to the Snowmass Recreation Center and Rodeo Lot trailhead.