Amy,
There is also a new article in the most recent Arkansas Historical Quarterly (Spring 2007) "Thunder Across the Arkansas Prairie: Shelby's Opening Salvo in the 1864 Invasion of Missouri." It is about Jo Shelby's attack on the rail road/hay stations between Brownsville and De Valls Bluff in July of 1864. This is when he captured most of the 54th Ill and a detachment from the 1st Neb., and in effect severing Steele's supply line in preparation for Price to maneuver out of Arkansas (and into Missouri for his invasion).
-Scott