We were in St. Martin two years ago with the Celebrity Millennium. It was easy to walk around. There was not enough time to go to the French side and get back without fear of missing the ship for us. Celebrity is not as kind as RSSC might be when a passenger is a little late, something we would never want to chance on any ship. There is a lot of traffic, we were told returning to Philipsberg.
We just walked around off the dock and had a wonderful lunch at the end of the main street at a beachfront cafe. We enjoyed it very much. I bought some earrings at one of the jewelery stores as my souvenier.