Since it's a dreary Saturday morning, I fiddled with routeslip.com and think I figured out how to enter the D!ckerson/Poolesville route. Hope this works.
Caveats: For some reason, it thinks there's a spot in the middle of the route that's at 0 ft elevation. That big downhill that the elevation chart shows doesn't exist. Also, though I did my best to follow the road very closely to get the distance right, it ended up 0.4 miles shorter than the cue sheet I have, so keep that in mind when looking at the cue sheet from routeslip. It says 39.3 miles total, mine says 39.7.
http://www.routeslip.com/map.php?map=8127