Try running a search on DigiTrad and Forum Archives.

I'm pretty sure that I've seen at least one thread on this lovely song here in the past year or two, and I "Harvested" the lyrics from it.
You may find several variations of this piece, as it seems to have "evolved" somewhat, and I don't know how old it is; as I recal it's fairly contemporary - within the last 40 years or so.

Good luck finding the score; ye'd probably do better finding a CD with the track on it and learning it by ear. If you play guitar, it lends itself well to a nice rolling 3/4 fingerpick with plenty of bass runs, IMHO.