"Corduroy Road" in my experience refers to a temporary work road lined crosswise with small logs. It a useful way to cross wetland or other undeveloped areas. No roadbed is needed. We made use of the ones that the logging crews constructed in the Maine woods when I was doing reconnaisance geology mapping for the State back in the early 1960's. In a few short years the logs rot out, and the Corduroy Road is no more than a bumpy memory.

I assume something similar is being referred to in this song.

Cheerily,
Charley Noble