Dear Spleen (I'm sorry but I can't recall your real name though I daresay I could work out the anagram); the songs of John Reilly are well worth exploring. I don't think that the Topic LP of his songs The Bonny Green Tree sold many copies as I have had to wait some years before I found a second-hand copy for sale. Malcolm Douglas very kindly let me hear his copy a few years ago when I first expressed an interest in John Reilly, and that was a gesture I remain very grateful for.
I think that the Irish Traditional Music Archive (or possibly the UCD) hold Tom Munnelly's recordings of John Reilly, but the recordings by D.K.Wilgus are held in the Ethnomusicology Archive at UCLA (that's California).
The last time I checked the collection's online archive it listed all the recordings made by Wilgus of John Reilly and other Irish singers and musicians amidst a huge quantity of material from all around the world, but a quick look today suggests that while some recordings (or extracts from recordings) can be heard in a digital library it is much harder to locate the details of the recordings. The archive nevertheless is a priceless source of ethnographic recordings and it is well worth exploring.
Matthew