Although I don't have an answer to your specific questions, I thought I would offer this information: A few people in my group on the Carnival Liberty last year took the ship's tour of Kayaking in Bio Bay when in port in San Juan during the evening. YES, Bio Bay is quite a distance from the ship. I normally always use independant tour operators, but for this one due to the distance involved and the fact that it is evening, I would recommend using the ship's tour.