After docking in Gatun Lake, only people on ship sponsored tours are allowed off the ship (this is controlled by the PCA - Panama Canal Authority.) You are tendered to shore where you will meet up with your shore excursion. A group of friends and I did the train excursion in the deluxe vintage dome car - the extra money to get on that car is worth it! The views from the upper deck are wonderful. It takes about an hour to go from Cristobal to Balboa on the Pacific side on the train. The bus tour for the most part on this end of the country was a bust - the only interesting thing was going to the Miraflores locks and watching ships going through there. We happened to be there at the time the people who were on the Ocean to Ocean tour arrived on the Pacifc Queen and we were able to watch them descend from sight as they were going back down to sea level. Then it was back on the train to return to Cristobal. We were then bussed to the ship which was docked at Colon at pier 6. There is a nice shopping area right at the dock and there is a cultural show that is put on there as well.