My mom spent 6 nights on the road adventuring through Arizona in October and it was AWESOME! We flew into Phoenix and did a one-way car rental to Vegas.
CAR RENTAL TIP: We saved 40% on our car rental by renting from outside the airport. I'm not sure if this is with all airports or just ones in Arizona or the United Stated but we managed to drop the rate from $830 to $470. I seriously almost had a heart attack when they told me the total when we arrived at Enterprise in the airport. How did it go to $40/day to over $800?! AIRPORT TAX, that's how. We took an uber to an enterprise location 1km away from the airport and the price dropped by almost 50%.