If you want to drive out to Front Royal, there are some great places along Skyline Drive to shoot a car against the mountains or the Shenandoah Valley. I haven't been to Great Falls, but I hear it is spectacular as well. There is also the Sully Plantation along Route 28 between 66 and 50, as well as Sky Meadows Park just past The Plains off of 66
http://www.dcr.state.va.us/parks/skymeado.htm.