I haven't looked up the links, but it reads like a modern composition

the meaning is something along the lines of

return, fair maiden, return my darling [literally my pulse, "a chuisle mo chroi", a phrase often Anglicised as acushla machree, means "pulse of my heart"]
Leave the evil and the city
Lest you fall ill shortly [galar can be physical, mental or emotional affliction; so this may be suggesting that the maiden will be morally corrupted by the ways of the city?]
Leave quickly

It's no wonder I'm depressed and tormented
when you are far from me
Glenncullen was once musical but now I see it under a cloak of sadness
Each and every day is like a long year

If I were to see you again, my intended,
Coming towards me willingly
There would be brightness of summer in the winter, without a doubt
And my heart would dance cheerfully