Mr. Martin,
You may want to obtain a copy of "Civil War Regiments: A Journal of the American Civil War, Volume Four, No. 1., The Mounted Arm in Tennessee." Pages 1-43 of the journal has an article entitled, "Defending the Confederate Heartland: Company F of Henry Ashby's 2nd Tennessee Cavalry" by James L. Mohon in which he talks about Colonel Ashby and his short postwar career and murder.
I hope this helps.
Respectfully,
Gerald D. Hodge, Jr.
War Between the States Historian
Historian: 39th Georgia Volunteer Infantry Regiment
http://39thgavolinfrgt.homestead.com/39thHomepage.html