My grandparents and I went on this tour with Mark, and he was an fantastic guide. Not only did he know enough about the area, history, geology, and plant life to keep up a steady stream of interesting information the entire trip, he was also hilarious. He made sure to keep our tour just a little bit ahead of the crowds. He even carried lots of extra water to continuously make sure we were keeping hydrated. He was also great about letting us know about local shoppers' tips when we stopped at different gift shops and things. He's an incredibly considerate and entertaining person, and one of the best tour guides I've ever had the pleasure of knowing.