I went on this tour a few years ago and its pretty much the same with a few additional activities + bits of information about the wild life and the importance of the swamp habital. It is more touristy now but well worth the time if you have never been.
The Jamaica photo project
Visit the far corners of the island, deep rural areas and cities and return safely with the pictures. submit your own photo
Its more of a rain forest than a place to swim. Plus when we went there the river was really rough. If anything you can get a good hike through the woods. If you want to nkow more about this place Elle has a more eloquent description from a time when the river was more calm. Note however that the gate might be locked with a no trespassing sign.