Just wanted to say that the tour was great. Five of us went, ages 7, 47, 48, 65 and 74. There was something for all of us. Our guide (can't remember her name) was very good. She not only told us about the history of the gardens and the Vatican, but also something about some of the Popes and how they related to the gardens. Some of the stories were quite funny. She pointed out some of the unusual plants and told us about some of the sculptures.
The tour does end at the museum so no waiting in line. Our guide gave is directions on where to go once inside so we didn't have to wander around and waste time.
There is a lot of walking on the tour, no sitting but you can rest in the shade while the guide talks. We brought water bottles and we kept them filled at the fountains in the garden. If you go in the summer be sure to wear a sun hat.