Directions to Bearfence Mountain: http://www.summitpost.org/crescent-rock/308242
Bearfence Mountain is the best rock scrambling opportunity you will get in and around Shenandoah National Park without making the day-long commitment and 2000 foot elevation change demanded by Old Rag. A very short trail in comparison, Bearfence Mountain can be completed in an hour or so. Although it lacks some of the climbing and crevice work you get with Old Rag, there is still plenty of boulder hopping.
Blazed 