I would try these resources:

The Last Confederate General by Larry Gordon
freepages.genealogy.rootsweb.ancestry.com/~minascpi/VaughnJCGeneral.htm
Lt Robert J Tipton Camp #2083 SCV Elizabethton, TN Vaughn's Brigade
O R Series for the PA 15 Cav
East TN Historical Society publication "Occupation of East TN and the defense of Knoxville" by Orlando Metcalfe Poe
Donahue "Don" Bible- author of East TN
Univ of TN Knoxville Library
Tennessee Civil War Sourcebook