There's a pull off at one of the trial's areas that holds a couple vehicles. If you're headed southbound on Beaumont, you'll see it on your right. The trail entrance is right across the road and allows for entry into C loop or the mid section of B loop. See if this works:http://www.google.com/maps?q=42.619015, ... =6&iwloc=A
The other option is to park at the trailhead and ride down Beaumont then cut in and ride some combination (B/2, D, A/2 or C, B/2, D, A/2, etc.) back to the trailhead.
It's a good spot to jump in and ride different loops without committing to the whole trail. I figured B would be a good choice for me to get a good workout since B is pretty much all I can handle right now. Maybe if I figure out how to shorten the gearing on my 1x9 cheaply I'll get an extra loop in there soon.