October Song has a pretty simple sequence. I think Williamson used to use an open G tuning on his guitar (but don't quote me on that)
You, of course, would have to use the key you're comfortable singing with.
Cheers
Ray
G             C    G C    G
I'll sing you this october song
G    D            G
There is no song before it
G             C    G   C          G
The words and tune are none of my own
G      D                G
But my joys and sorrows bore it

G          G7      C       G
Beside the sea the brambly briar
D               G
In the shade of evening
G         C   G C       G
Birds fly out behind the sun
G   D                G
And with them I'll be leaving