I play and study music of the old west. Part of that is the early songs and poems of the cowboy. John and Alan Lomax take up a good section of my cowboy library. Joe, it seems that you are looking for more that the usual material. So here is some Lomax on the fringe.

Cow Camps & Cattle Herds - John A. Lomax
The Encino Press, 1967
Introduction by John A. Lomax, Jr.
This covers songs but also cowboy culture in general.

Home On The Range by John A. Lomax
Published December 1986 by John H. Jenkins
ASIN B06XBLBD6G
This is a rough essay on the song by Lomax with corrections. You'll find some good material here on his discovery of Home on the Range.

The completed article appears in:
Half-Million Dollar Song
John A. Lomax
Half-Million Dollar Song, origin of 'Home on the Range'
The Southwest Review, Dallas, Texas,
Volume 31, Issue 1
Fall 1945
pp. 1-8.
Southern Methodist University Press

In the above articles and other publications, John Lomax claims that Home on the Range predates Dr. Brewster M. Higley but there are as yet no sources that support this.

Finally Lighter is correct that "Songs of the Cattle Trail and Cow Camp" consists mostly of spoken word poetry. But there are some pieces within that have become popular cowboy songs and some that were written intended to be songs.