Martin, there were a hell of a lot of Irishmen in California during the gold rush days and on into the railroading and entrepreneural days. I have no evidence against your use of "until" in the song. I would like to see a source for the song and wondered if it could be found in one of the song books that came out in California in the 1850s-1870s. The word could be checked to see if its use in Joe's unattributed version is in another version, or if it could be an error.

"Mind," in the sense of to obey, to take care, to listen carefully, is widespread in the States. It is very common in the South and West. My grandmother and my wife's mother both used it frequently (both imperious souls). It could have come with Irish immigrants, but on the other hand, its usage in that sense in English goes back to the 14th century (OED) so it could have been brought over by the first English-speaking colonists.

I can't see any similarity with "The Peeler and His Goat" (in the DT) except meter, which may be said of a lot of other songs as well.