For historical interest... my father didn't sing, but used to recite the poem. He had one verse from his childhood I've never heard anywhere else... and of course, would not be appropriate. I suspect it was some local parody.. As a kid, I never thought of it as racist, just funny.

" Old Dan Tucker was a fine old booster,
He used to ride a bob-tailed rooster.
Rode him up a hickory steeple,
And there he found some colored people.
Some were black... and some were blacker.
Some so black, they chewed tobaccer."