What was I thinking? In the key of A, Gallowa Hills, with its emphasis on E, would be in the Mixolydian mode, not Phrygian.

I have played a lot of tunes over the years, and few of them are actually modal throughout. Some seem to start out in a mode, but give it up and end on the tonic like most modern tunes.

Gallowa Hills may not be in the mode asked for, but it's worth learning, just to know a modal tune.