I found these tracks on ADVrider.
PA, MD, VA, WV Routes (Dirt Roads) - ADVrider
PA, MD, VA, WV Routes (Dirt Roads) GPS Tracks - Northeast, Southeast & Florida
http://www.advrider.com/forums/show...
Not all of the files in the zip were in GPX format so I used :
GPS Visualizer
GPS Visualizer is a free utility that creates customizable maps and profiles from GPS data (tracklogs & waypoints), addresses, or coordinates.
http://gpsvisualizer.com
to convert that Garmin GDB file format into GPX. The resolution of the tracks isn't great, but at least it gives us some areas to explore.
Unpaved Roads in Maryland - courtesy of ADVRider.
In looking for more off pavement opportunities in and around DC, I found these tracks on ADVRider. The best off-road sections are reported to be around GreenRidge National Forest.
http://www.dnr.state.md.us/forests/StateForests/greenri...
According to the thread, the best roads are around Green Ridge State Forest:
Green Ridge State Forest | Forest Service | Maryland Department of Natural Resources
There are supposed to be good unpaved roads around in this area.
http://www.dnr.state.md.us/forests/...
Know of any unpaved roads in Maryland?