Here is a note that perhaps answers Joe's query about the provenance of 'The Cowboy' or 'Cowboy's Soliloquy' and may save Sandy the trouble of a bit of fossicking in his library. I didn't have this earlier because a friend had borrowed my copy of White's book. White quoted the first verse of Sprague's rendition and appended this note at the end of his chapter on Sprague:

From 'The Cowboy' (Victor 21402) sung by Carl T. Spague. A full text appears in Clifford P. Westermeier 'Trailing the Cowboy' (Caldwell, Idaho: Caxton Printers, 1955, pp 263-264. Titled 'The Cowboy's Soliloquy', this was taken from a Trinidad, Colorado, newspaper, 'The Daily Advertiser' for April 9, 1885 which credited the poem to Allen McCandless. Richard E. Lingenfelter and Richard A. Dwyer reprint this 1885 text in 'Songs of the American West' (Berkeley and Los Angeles: University of California Press 1968, pp 342-43) with the tune from the 1910 Lomax collection 'Cowboy Songs and Other Frontier Ballads' (New York: Sturgis & Walton Co, pp 98-99). [Note 1 at page 195 of John I. White 'Git Along Little Dogies: Songs and Songmakers of the American West' University of Illinois Press 1989]

Cheers, Stewie.