Click here for a 1912 Victor recording of "Low Bridge, Everybody Down," by tenor Billy Murray, Victor-1720

This page (click) gives a full description of the recording.

But heck, we still haven't found sheet music. Best I've been able to do is this page, which has the cover of a 1913 copy of the sheet music.

There's a 1929 Vernon Dalhart recording of the song on this page (click) and this page (click)

-Joe-