Stem Cell is accessed by Tim's Trail
or other nearby trails from the bottom of the slope. This trail is 3.0 miles and normally traveled in a clockwise fashion (as mapped). It's 2.0 miles uphill, 1.0 mile down. If you run it backwards, it's that much harder on the ascent.
The start of the loop begins with a relatively mild gradient that takes runners up many switchbacks to the top. The climb is fun and has varied terrain as well as a nice rest halfway up. Once you hit the top, there's 1.0 mile descent to the bottom which includes a roll-down or drop for bikers.
When finished, most people will run out Tim's Trail
back to the top parking area.