We're not really roughing it kind of people but look to spend 2 nights in Flagstaff in mid October and spend one day going along the GC drive -west to east and returning to Flagstaff. We thought we'd pack a lunch and meander along the south rim to the exit. It's been 30 years plus since I've been there.We'll also go to the Lowell observatory one night.
Sound like a plan? Anything to avoid or include from the park entrance going east - Google Earth looks like a simple drive to putter along in a rented convertible.