Cross the Sierra Madres twice. First the Sierra Madre Oriental between Monterrey & Saltillo. Then the Sierra Madre Occidental between Durango & the Pacific coast. A very scenic drive, interspersed with some dull flatland driving.
Drive over world-famous Baluarte Bridge (one of the official wonders of the world). Hotels, RV parks and parking spots detailed as well as road directions. Great ride for motorcycles. Birding and Alpine lodging just off the toll road in the Sierras. That part is safe & interesting to visit.