You might also post a query on the Kentucky board of this website. And if you could let us know how your search turns out, it would be appreciated. We all benefit in knowing what research methods work for others.

FYI--if you would like to find out the general experience Andrew Jackson Dewitt may have had in northeast Missouri in late 1861 and early 1862, I would recommend you obtain a copy of "With Porter in North Missouri," by Joseph Mudd. It should also provide you with insights into why Dewitt may have left Missouri and headed back to Kentucky, if that is in fact what he did. Northeast Missouri Confederate veteran Joseph Mudd ended up going to Maryland, and provides a pretty good account of his harrowing escape from Missouri, and the reasons why he left. If Dewitt did serve in northeast Missouri during the time frame in question, he probably did so in relatively close proximity to Mudd.