What a coincidence. I just thought of this, and typed KML into the TM search box, and found that it had been suggested four days ago.
I think the way I'd use this is to convert my Untraveled routes in a particular state into a KML file, and then layer it on top of Google Earth on my Android phone. (I wish you could layer KML on top of Android Google Maps, but you can't.) That way, I could visually see where I should go in order to clinch new roads. Seeing Traveled routes wouldn't be useful. Also, I'd rather not have the map cluttered with translucent lines indicating "unhighlighted" routes. (I feel the same way about the TM site, but that's been discussed in another thread.)
