It seems that everyone knows a slightly different version of this song, here are the letter notes for how I know it - let me know if your version is better :D
GÂ Â Â Â Â AÂ Â ^C - ^CÂ Â ^CÂ Â Â ^CÂ Â Â A - G
She'll be coming round the mountain
EÂ Â Â Â Â Â GÂ Â Â ^C
When she comes
^CÂ Â Â Â ^DÂ Â ^E-^EÂ Â ^EÂ Â Â ^EÂ Â Â ^G - ^E
She'll be coming round the mountain
^DÂ Â Â Â ^CÂ Â Â ^D
When she comes
^GÂ Â Â ^GÂ Â ^E - ^EÂ Â Â ^EÂ Â Â ^EÂ Â ^D - C
She'll be coming round the mountain,
G - ^CÂ Â Â Â ^CÂ Â Â Â GÂ Â Â ^D-^C
Coming round the mountain,
^E - ^EÂ Â Â ^EÂ Â Â Â ^EÂ Â Â ^D - ^C
Coming round the mountain
^CÂ Â Â Â Â BÂ Â Â Â ^C
When she comes