Daniel B. Blackburn, enlisted as a Private in Company C, Black's Battalion, Forrest's Cavalry, "was taken prisoner under arms and after a pretty brisk skirmish" near Jackson/Trenton, Gibson County, Tennessee April 19, 1863, arriving Military Prison, Alton, Illinois April 30, 1863, released on taking the Oath of Allegiance to the
U. S. on May 19, 1863

His records are found in Microform M269, Tennessee CSRs, Roll 359 Miscellaneous, Tennessee which may be procured at:

http://history-sites.com/research/index.html

His reference card in the roster of Company C, 3rd Tennessee Cavalry carries the notation: "See 5th Battalion Tennessee Partisan Rangers." I could not locate these records.

Regarding no widow's Confederate pension, Confederate Tennessee veteran's pensions were disallowed for any who pledged allegiance to the US prior to Lee's surrender April 9, 1865. I assume this applied to their widow's also. However, she would have applied in Georgia, I do not know if they had a similar restriction.