Saint Johns: I have to mention this! I was in the US Navy for many years on a carrier (which is similar in size to the cruise ship) and it took us six tug boats, and the better part of an hour, to dock the ship when we were the only boat on the peer. Our ship pulled in to the dock between to other cruise ships having not more than 50 feet on either side and backed it in like a car in less that 20 min without a tug!
In this port we decided to follow the advice of a cruise critic member we met during the cruise critic meet and mingle. She was from Texas and had cruised several times before. Her advice led us to Sapphire Bay for a relaxing day on an uncrowded beach. There we went snorkeling, and enjoyed being catered to while laying on the perfect beach over looking clear waters. It was wonderful. (about $35 each which included ride, equipment, and a drink).
St. Martin: It was raining hard the first hour after leaving the ship and was a little cooler making us glad we did not have a prepaid excursion. We took a taxi to the main shopping area and were slightly concerned about the flooding roads but they drained quickly after the rain stopped. The rest of the day was spend holding hands and shopping. We ended back a local beach cafe where we tried to enjoy dinner even though the locals kept bothering us to buy their stuff. Heading back to ship we were entertained by island songs while on a water taxi.