I used to live in Jackson - -
Jackson, Wyoming that is.
But there are a number of great back roads from Jackson, Mississippi.
Here are some county road maps:
http://www.gomdot.com/Divisions/Inte...Maps/Hinds.pdf
http://www.gomdot.com/Divisions/Inte...aps/Warren.pdf
Champion Hill Rd and Warriors Trail thru Edwards and Bovina appear to be more backroadish than US 80.
You'll be following almost the exact route Grant used to advance upon Vicksburg.