John, Kirby, Jim, and Ryan,
I pulled up the Union provost marshal entries that concerned our Crabtree from the online Missouri State Archives kept by the Missouri Sec'y of State's office. Within I made two discoveries that add to our body of knowledge or at least corroborate some of what we already have about the man.
One entry mentions a "list of names attached to letters found on Crabtree, Missouri guerrilla." This brief phrase tends to verify what "the Central City and Brunswicker" newspaper of 16 October 1862 wrote about Crabtree bringing letters from southern troops elsewhere back to their family and friends in central Missouri. Sadly, the list of names no longer exists, if I read the entry correctly.
Secondly, another entry in the Yankee provost marshal's files states that E. B. Farley and a Mr. Cummins of near Tuscumbia, Miller County, were arrested as of 28 September 1862 "under suspicion of association with the late Crabtree." Even if Farley and Cummins were innocent of the charges, this phrase indicates that Crabtree was dead by 28 September 1862. Union records also show that Missouri Union forces pursued Crabtree and one of his batches of southern recruits during August 1862, while Crabtree and his cadre were taking them south. Therefore, we know that Crabtree was alive and well in August 1862, but died by 28 September 1862. I am now convinced we need not seek Crabtree after that date.