Jed, you might also find the poems/songs of Paul Laurence Dunbar of interest. He wasn't born until 1872, but the song/poems he collected in Howdy honey, howdy presumably came from earlier times, though I don't know if they'd be specific to runaways. I think that site has the entire contents of that book, if not and there is one of the pieces you want to read, let me know and I will copy it into here. If you do a search on him or the book title, here, you will find one of the songs, Bury me under the willow, already posted.