The music for "The Plow that Brioke the Plains" was written by Virgil Thompson, who later became a classical music critic (and a very articulate and provocative one) for the New York Herold Tribune in the middle of the 20th Century. The score incorporated popular melodies, cowboy songs (including one that mega-composer Aaron Copland would also use), and what-have-you in a pastiche that somehow works, at least for the film. It's fairly obvious (to anyone who has spent a lot of time listening to American classical music of that time) that Thompson influenced others even as he was influenced by them. It's a peculiarly American style, with a lilt all its own and a humor that can creep up on you.
The rest of the film, unfortunately, hasn't aged all that well. It's a bit like finding, in a musty old library, a promising monograph on the history of a city or a region written by someone in town who thought he had a gift for such things, only to find adolescent, unsupportable, and insufferable platitudes and a dearth of much-needed facts. And zero -- count 'em, zero! -- specific stories that could have warmed up the narrative, even a little bit. Yuck.