Was on the C&O two weeks ago from Cumberland to DC and had the same experience. I made a point of jumping off at Williamsport for a scenic detour through Sharpsburg then bailed again at Brunswick to head south and hit the W&OD. Was the best decision I ever made and saved my sanity. I'll never forget the look on the B&B owner's face in Harpers Ferry when I arrived covered in mud (me, bike, panniers) and proceeded to hose everything down outside. It was "why did I agree to have a cycle tourist here" transitioning to "thanks god he's not tracking all that mud into my house."