First of all the drivers were very good and the staff as well. Viator does not disclose that you have to get off at Old Town, and wait for a new trolley and driver. We waited 30 minutes. When I complained to the staff, they said if you booked on our website we tell you, Viator does not. Also, we got off and walked around twice, and could not get on the next trolley because it was full. This was not a pleasant experience. We had to be back by 4:30 after starting at 11:30 and barely made it. I would not do this again.