As mentioned, you'd need the FAA validation, and then the rental checkout. I suspect the checkout would be very thorough, and not worth it for a single flight - they'd want to know you were competent flying at high density altitudes (Grand Canyon is HIGH!), and also in a very busy traffic environment, with airspace that is not totally simple.
When I flew over the Grand Canyon, I got around these checkout issues by hiring the plane in Florida and going the long way
