Need Help with a route from Yuma AZ to Illinois in mid April

Maybe you aren't planning to stay in the coach, but I would advise that you be ready to do so. It is rare and you don't say where Illinois, but it can still get bad in April. To this end, have the coach provisioned for three days before departure. That way, if things go bad, all you have to do is find a safe/flat place and wait it out. When we were still employed, we only got to travel at the ends of the seasons and we did have to find a place to hold-up on a couple of occasions.

Matt