First of all, the paid tours provide access to areas not accessible through the self-driving route. And it's well worth it. There's so much more to Monument Valley than I ever realized. The tour gives you a look at the "back country" part of the Valley, including the arches--featuring the Grand Hogan--and a sample traditional Navajo living area. The tour guide was very knowledgeable, and was able to answer all of our questions. We had a 3+ hour trip through the Valley, and the price was well worth it. I would highly recommend this tour if you really want to see the entirety of Monument Valley.