On Hard times, I think the line is the end of the row, not road.
I also think the reference to lost his knack, is about the loss of one's dreams, hopes and aspirations.
His knack for doing his soul's work, he forgot that song, the song in your heart that keeps you moving forward, woke up one morning and the mule was gone. Metaphorically the mule was his dreams. Life had passed him by. One day you wake up to realize that you're never going to do the things you always dreamed you would.
Possibly the saddest lines in the whole album.