Unless I'm mistaken, this is the best western story I ever came across. Read it years ago, though. But I believe this is the one...the Amazon description sounds right. Excellent piece of work.
The Canyon by Schaefer
I recall Little Big Man being good, too. The hundred or so pages about Custer's defeat were as good as any 'historical fiction' as I've ever come across as far as mesmerizing with words. Thomas Berger wrote that.
J. Frank Dobie was a good writer. More of a historian. 'Yaqui gold...etc' is a good book. The Longhorns. Yeah...Dobie for the 'real life' stuff.