From Judd's Bridge, follow the road towards Washington and Steep Rock, go straight on the road that is perpendicular to the bridge. Follow it up into a curve and on the left there is a house with a garden behind it. The trail starts next to the garden and is mowed into the high grass. This trail is decent 4x4 style trail and single track all the way to Steep Rock, where you can ride to the pinnacle on the trail that starts right after the foot bridge and its support cables. The pinnacle has great views and an awesome down hill. On the way back, take the road that goes over the tunnel, and take a right at the bend, between two large boulders there is a small trail. Take this for 1/4 of a mile and it reaches the powerlines where you can follow the 4x4 trail for a mile uphill, turn around and ride back for a rough, but exciting downhill. Follow the trail past the powerlines to the dirtroad blocked off by rocks, where you can ride a short downhill back to Judd's bridge where you parked.
Start either from Steep Rock parking lot, or Judd's Bridge in Roxbury.
http://www.singletracks.com/item.php?c=1&i=6625