Neil Young's "Helpless" and Bob Dylan's "Knocking on Heavens Door" are nearly identical and very easy to play.
Helpless:
C - G - F per line of lyrics (including chorus)
Knocking on Heavens Door:
C - G - Dm for first line of lyric (including chorus)
C - G - F for second line of lyric (including chorus)
And then just play these lyric structures over and over again until the end of the song!
