Great comments in this youtube interview with Peter Fonda.

Start at 5:25 for description of private screening for Bob Dylan where Roger McGuinn gets the torch passed to him.
McGuinn’s solo version is in the film. Sounds like all he wrote was “ All they wanted/ Was to be free/ And that’s the way/ It turned out to be.” ..to make the song less “pastoral” for Fonda. Wow. Talents and collaboration making it happen.