Renting RV Late Dec. - Phoenix-Denver...All Routes Unsafe?

Spend a night or two at Dutchman State Park near Phoenix, then head northwest to Dead Horse Ranch State Park. Go west to Lake Havasu and check out the London Bridge, then loop south to Yuma before coming into Tucson. Check out Bisbee, or go down to the Chiracahua National Monument and the OK Corral in Tombstone. All southern destinations that should have great weather and beautiful scenery!