It's a valuable document in the history of the song, but I must agree with Q about the question of the date. "Harlan 1885" alone shows that the manuscript couldn't have been written in 1879.

Just what the two county names and dates mean is a little uncertain. My guess is that the singer told the collector - presumably (though not certainly) a grown-up Edwin Ford Piper - that he or she recalled hearing the song in 1879 and then heard it again in 1885 in different county.

Memory plays tricks (hence the "folk process"). It seems likely, though, that the source singer was recalling fairly accurately a song learned in the mid 1880s, if not a few years earlier.

The text is perfectly lucid, which suggests a reasonably accurate recollection. To me, "consider a while" seems more likely to have become the familiar "come sit down a while" rather than the other way round.