The U.S. Army's Combat Studies Institute press have just published "Battlefield Atlas of Price's Missouri Expedition of 1864" which was authored by Charles D. Collins Jr.

The maps look good on first inspection, and is available as a free download as a .PDF from the page link below.

http://usacac.army.mil/sites/default/files/documents/cace/CSI/CSIPubs/Prices_Missouri_Expedition_web.pdf

Alan Thrower
England