I suggest you see if you can get a copy of this book at your library or order it via inter-library loan (or purchase)

http://www.amazon.com/Frontier-Defense-Civil-War-Association/dp/0890965943?ie=UTF8&ref_=cm_cr-mr-title

Smith, David, P. Frontier Defense in the Civil War: Texas' Rangers and Rebels (Centennial Series of the Association of Former Students Texas A & M University) (Paperback)

This 237 page book tells the story of the defense of the Texas frontier from Indians, Jayhawkers, Unionists, and Deserters, by Texas Rangers, Texas State Troops, Frontier Regt, Bourland's Border Regt, and the Frontier Organization. Author David Paul Smith, has an extensive set of endnotes, index, and bibliography, which make this a great book for those who wish to probe this turbulent period in more detail.
The majority of the book deals with the region North and West of Fort Worth, although all of the Western frontier of Texas is covered. The author combines the facts with explanations to cover a period when reliable records are scarce and myth/legend are legion. Particularly impressive are the descriptions of the Elm Creek Raid and Battle of Dove Creek.
In addition, Frontier Defense also briefly covers strategy & tactics used before and during the War Between The States.
Simplified maps of the frontier districts are included, but a good map of Texas is needed unless the reader is very familiar with the frontier outposts. The free Texas Historical Commission map "Texas in The Civil War" is an essential item needed to accompany this book.
The border with Mexico, Gulf Coast, and Eastern Texas are not covered as this regions are beyond the scope of the work.