All this talk of emigrant/immigrant songs reminds me of a classic which I think is a must for your programme. It is an old English(and no doubt Irish and Scottish and Welsh as well) emigration song called variously "Chase/Hunt/Shoot the Buffalo". It is also well known in America(perhaps starte there?). Anyway it's got three totally different chunks of very important history.
(1) economic pressures to emigrate to America
(2) Buffalo hunting (eco connections etc etc)
(3) Attitudes(quite unpleasant) to the "wild and savage Indians".

And it's also a great song. What more could you want? A must, I reckon. I'm sure it will be in the Digitrad under one or other title. Or it might also be called "The Pleasant Ohio".