http://www.folkinfo.org/songs/displaysong.php?songid=611

The song seems to have a very simple harmonic structure, in the key of G.

I'd just play around with G, C and D until something worked as a starting point.

I don't have an instrument to hand, but I suspect something like this would work.

| G / / | G / / | C / D | G / /|
| G / / | G / / | C / G | D / /|
| G / / | G / / | C / G | D / /|
| G / / | G / / | C / D | G / /|