A few years ago, I went to the Maya Riviera-about 2hrs south of Cancun. Not sure what condition it will be in after the storms, but Sian Kaan (sp?) was ABSOLUTELY amazing! It's a big biopreserve. We did a tour through it with an adventure guide group. The picked us up at the resort with a bunch of jeeps-each group got to drive their own jeep. You go through the jungle, then out on the ocean and check out the mangroves. They took us snokeling. Then to Punta Allen, which is a little fishing village where they had lunch waiting for us. We also stopped somewhere with brackish water to go swimming-that's a mix of fresh and salt water. That was SO much fun. It was an all day evernt. I don't remember which company we went through, something like "Adventure tours?". The guides were amazing. They were fluent in several languages, so they broke everyone up by language. They were extremely knowledgable about everything.