As usual, you guys are fantastically generous with your help on this. Ya'll are what make the Internet great. Well, ya'll and the binarie groups. :)
Barry, I absolutely agree that going further in a search for Shenadoah as a shanty, beyond what has been done, is futile. My idea of Sheenydore, Ireland needs to be lost at sea. It was a shantie and, to a certain degree in the case of this song, a shanty is a shanty, w/no "original version" one could accurately believe in w/o the help of a time travel machine.
I would guess I need to head onto land w/this now.
Tracking down the earliest printed versions of the song may help see where it "goes West". Any idea on archives like that?