Flag Staff to South Rim

Ernest...Are you driving the MH and toad to the GC? (which is what I assumed.) Or are you asking just for a day trip in your toad to the GC? If just in the toad, then I would do as darsben1 suggests. Enter the east gate (89 northeast from Flagstaff to 64) and exit the south gate back to Flagstaff (or wherever you are staying). But I would not bother going in the east gate with the MH if you are staying at the GC and can do the eastern road viewpoints, etc. in your toad.