If you're looking for a route off the interstates and a bit off the beaten path try this route.....you don't say WHEN you're planning this trip so I'm assuming the snow will be gone....
Leaving Flag, e/b I-40 to Winslow Az. Pick up AZ 87 South and follow it to the 202 Loop in Mesa. Take the 202 Loop E/B to US 60 E/B. This will take you up and into Globe Az. (Nice Casino Campground with FHU) From there take US 70 E/B to Lordsburg, New Mexico where you can pick up I-10 E/B. There's not too many choices heading E/B from there. If you want, you could pick up US 180 in El Paso, which would take you north and east again through Carlsbad Caverns and drop you in Fort Worth/Dallas. Eventually, you'll have to head south but look at the above route and decide where you'll do that....
All roads indicated are a fairly easy drive which I've done with the rig in my signature plus the toad....Dennis