Cross at Santa Teresa but don't take HW 45 all the way south to Chihuahua. That highway sucks on a KLR! Cut west at Villa Miguel Ahumada and take country roads 19 and 27, and 5 down through the Mennonite country to Cuauhtemoc. This route is a much nicer alternative to the highway.
I was in Louisville last Thursday. I have family there!