If you haven't already done so, you should read "Kirby Smith's Confederacy: The Trans-Mississippi South, 1863-1865," by Robert L. Kerby [Columbia University Press: 1972].

It's a fascinating, detailed study of the Trans-Mississippi Department (Kirby-Smithdom), it's strengths and weaknesses, the good and bad of Kirby Smith's command structure, the (mostly bad) attitude of Richmond towards the TMD, etc. Lots of tables and charts. Highly recommended.