This weekends' must hear: The Log of a Cowboy.
"The Log of a Cowboy is an account of a five-month drive of 3,000 cattle from Brownsville, Texas, to Montana in 1882 along the Great Western Cattle Trail. Although the book is fiction, it is firmly based on Adams's own experiences on the trail, and it is considered by many to be the best account of cowboy life in literature. Adams was disgusted by the unrealistic cowboy fiction being published in his day; The Log of a Cowboy was his response. It is still in print, and even modern reviewers consider it a compelling classic. The Chicago Herald said: "As a narrative of cowboy life, Andy Adams' book is clearly the real thing. It carries its own certificate of authentic first-hand experience on every page." (Introduction by wikipedia)"
If that is too realistic and you desire a pukka cowboy swashbuckler, there is always The Bear Creek Collection and if that is not enough, The Bear Creek Collection 2. From the blurb:
"Breckinridge Elkins is the roughest, toughest, fastest-shootin’, hardest-fightin’ feller in the Bear Creek settlement, and probably in the entire Humbolt Mountains. As he travels further from home, he single-handedly takes on outlaws, settles (and starts) feuds and tries his hand at romancing the girls. He also discovers a lot of strange customs among other folks, such as building houses out of boards and wearing clothes that ain’t buckskins. Set in Nevada during the late 1800’s, this collection of stories is a great rollicking romp through the American frontier as seen through the eyes of one of the most enjoyable characters created in the history of tall tales." (Summary by RK Wilcox)
And for something inbetween the two offerings, there is of course Buffalo Bill's memoirs: "The Life of Honorable William F. Cody ".