Bryce, no I am not familiar with the book, but thanks for mentioning it, I will put it on my list of wants. Here are several more titles that mention McCausland, though I have not read them.

Unreconstructed Rebel, The Life of General John McCausland, by Michael Pauley, 1993.

A Mennonite Journal, 1862-1865: A Father's Account of the Civil War, by John R. Hildebrand, 1996

Jack May's War: Colonel Andrew Jackson May and the Civil War, by Robert Perry, 1998

And I just found this on Ebay, letters from a cavalryman of the 14th VA