The wife and I went in March. We rented a car online, the wife got us a Mustang convertable for $20 a day plus insurance. Check with your insurance company and they might cover it without paying the extra, or your credit card company. I kick myself in the ass for not keeping it all week. Taxi costs were crazy, well worth having a rental.
We took a day trip to the South rim of the Grand Canyon, long day but well worth it. Watch out for the time shares, they say hour and a half but took 4 hours. Still got the free tickets to blue man group and dinner coupons.