We were in Fort-de-France, Martinique as a stop last year, and it was the only island where we couldn't wait to get back on the boat. I have been to dozens of islands and this was the filthiest, least attractive, least friendly island; made Jamaica friendly, amde downtown Newark look lovely. It was a good call to change ports. In the defense of Martinique, we did go on a snorkling excursion that afternoon to a section outside Fort-de-France, and that was delightful. Swimming through shimmering silver walls of schools of herring; saw octopii, heard whale calls... just delightful. The surrounding landscape was not upscale, but more kept, and the people marginally hospitable. Our friends who did the rain forest tour were pleased with that, too. But stay out of the city. Good luck with your alternative plans.