Man, I love this book. I tried reading it once before, 10 or 15 years ago, and let the "frame" stand in the way. (To be fair, it's pretty lame—as most frames are.) So glad I gave it another shot, though, and got past that this time.
Cather's writing here is on a par with O Pioneers!. She fleshes out her characters and their relationships fully, from the inside. Realist writing is often restrained by Chekhov's insistence on "removing everything that has no relevance to the story." Cather's realism is never so minimal, and is all the more real for it. She fully incorporates anything that will help build her characters. The connections may be coarsely drawn, in the way that human relations can be. But these loose, ragged details are not, as Chekhov might call them, unkept promises. In the end there is a very human essence to her people and her places, that can only appears from a slight angle. She could never have shown it directly. I come away from her best work with a feeling, more than an idea. Which is exactly how I came away from this one.