With no sightseeing and going by most direct route, it's 3 days just to drive from Calgary to Yuma. So - the only thing you will have time to see in 4 days is the Grand Canyon, and that will be a bit rushed - you will have about half a day to spend there. You will need to plan overnights in Dillon MT and Panguitch, and the 3rd night in Tusayan on your way out of the GC.