Okay--I believe the final stanza is:

On with old Morris then, fight the old fight again
They just pay taxes to be spent by you
Down with the surging mass, up with the holy grass
Fight for the park's right, ol' Morris on the move!

With that I think we have more or less the complete lyric, though I don't know if I've got some of the words right.

The tune is a fairly standard G-C-D thing with an A thrown in here and there--if you've heard it, you can probably play it, though there's something about Pete's clawhammer banjo that makes even the simplest fingering shine.