You should also look into some of Jed Marum's songs (also a Mudcatter, and also a Texan!) He writes/performs a lot of songs dealing with Irish immigrants to America. Here is a link to the lyrics page on his website.

In particular, I'd look at Mary McGuill, a love song from a husband who immigrated first and is anticipating his wife's arrival, and at Look Ahead Tommy, which is an immigrant's advice to his grandson to build a better life in the new world.

You won't regret buying one of his CDs, even if you don't end up using the song in your show.

Marion