All of us were awed by the rich collection of buddist rock carvings from Tang dynasty onwards. I feel that the museum is a must go so you would get to learn about the backgrounds prior to heading out to see the Buddhas. As a result, if you do manage to hire a tour guide, and most important, a good one, it would be really beneficial towards having an enjoyable and enriching trip. You will learn about the amazing history of how Buddism originated from India and propagated to central Asia and different parts of China across many centuries. There are lots of walking involved. Be sure to go in your walking shoes. The weather was cool when we were there hence it was not physically taxing.