There are 3 options for this type of tour - check them all and compare which one would work for you. We bought the two day pass. We hopped off about 8 times over the 2 days and only had a long wait once to get back on. The buses with the live guides are definitely better.
Michael gave us an amazing history lesson as we looked at the sites he pointed out. He made the trip. Rock on Michael!!
Some of the buses have prerecorded messages - be advised