Angle of Repose
by Wallace Stegner (plagiarizing Mary Hallock Foote)
The original bits interjected by Stegner were trash. The majority that he plagiarized was eloquent, insightful, and a view into the "early US West" - a time period I previously didn't know much about.
If you choose to read this, I highly recommend either preceding or following with the following post examining the plagiarism: https://www.altaonline.com/books/fiction/a39179237/wallace-stegner-mary-hallock-foote-plagarism/