If you don't have a shuttle, start on the Fire Road at the Seneca Creek Trailhead, ride up the fire road to the top of Spruce Knob, 6 miles. Follow Huckleberry till you come to the first intersection, stay left on Huckleberry, then in a short distance you will go left again. Follow the trail till you come to Lumberjack trail and then across Lumberjack on a trail marked "to Seneca Creek" In a short distance, Judy Springs trail will take off on your left. Make sure your brakes are adjusted here because it is a couple miles of steep, offcamber downhill with some tough little dips with lots of rocks in them. Watch your speed because they come up fast. You will know when you are about there, because you will come into a nasty rockgarden on the side of a step hill. It can be ridden, just go for it. Stay to the right near the bottom due to a drop off before the creek. After a short climb and another short downhill you will come out a Judy Springs remote campsites, cross the wooden walk bridge and take a left on Seneca Creek Trail. This portion is a gradual climb for about 3 miles back to your vehicle.
If you have a shuttle, you can leave one vehicle at Seneca Creek Trailhead and drive to the top of Spruce Knob, however you will miss some awesome scenery.
Check the pictures posted.