89A from Slide Rock State Park to I-17 has got to be one of the most spectacular drives you can take. Be sure to jog off 89A to the loop road when you have the chance or you'll miss some great scenery. You don't need to spend money on any off-road tour or any kind of organized tour for that matter. The self-guided tour is just fine. Be sure to stop off every now and then to take some great pictures. The worst part of the drive in my opinion is when you hit that very touristy (and luckily very short) stretch of 89A that I guess amounts to the business district of Sedona. Watch out for the throng of people but definitely breeze by the fake new age crystal or yoga shops and spend your time (and not your money) on the natural beauty of the surroundings.