@frogman
It's Important to distinguish between folk music and the classical music inspired by folk music.
There may be examples where they are hard to distinguish, but Ashokan Farewell is not one of them. It is so very clearly on the folk music side. First, watch Jay Ungar play. He never leaves first position on the fiddle. That is typical of folk music. I've never seen that on any piece considered classical. It's a very easy, simple tune and the reason that millions of amateur fiddlers play that it, most often by ear. The tune's simplicity is marked by having only one accidental note, one time anywhere within its two parts. It has a VERY easy harmony. I'm not much of a musician but I have improvised harmony on that tune as I play it on a folk instrument. All of these are indications of simple a folk tune. Also that its composition was inspired by other, traditional, folk tunes.
So for Ashokan Farewell it's not a close call--for a tune we all love! But, just a good tune.