What follow is JUST MY SUPPOSITION, LACKING ANY AUTHORITY OR PRETENSE OF ABSOLUTE TRUTH !!!
I think it's posible that Weatherly was making reference to the Irish Potato famines. In many regions starvation was so bad the most folks died. If your family got some cash together and sent you to America... or any other place... you were going to probably live. If you stayed, it was likely you would die.
In Skibbereen 90% of the people perished of starvation.
Pipes were sometimes used to call passengers to embark on ships.
Or maybe Danny was heading off to his new carreer as a plumber.
FW wrote the lyrics in 1910. His sister tipped him to The Londonderry Aire two years later in 1912. I may have given the imperssion that she wrote him in 1913.
Honestly, I like the tune and the lyrics. It's the bad performances that curdle my whey. It's a beautiful thing when well done.
And, like the Star Spangled Banner, the choice of key should be made by the singer, not the piano player. You may not be able to sing the whole range of the tune in F, but C might suit you fine.