Route advice for IN and OH

[bikedentist]

I'm planning a trip from MN to SC in September and need some help from those familiar with the parts of IN and OH through which I will pass.  I will leave the ACA North Lakes route in N. Judson, IN and plan to go from there to Huntington, Greenville, OH, Washington Courthouse, and finally Portsmouth.  This is the path I have chosen generally, but I don't have a clue as to specific roads to get from one place to another.  I want to avoid heavy traffic in Dayton and busy highways with little or no shoulder, obviously.  If anyone could suggest a route through this region, that would be great.