We are sailing to Costa Maya and Cozumel in October. What are the must see/do things in these two spots? I was thinking of the Chacchoben Mayan Ruins in Costa Maya, is it good or waste of time??? We were thinking of the Catamaran Sail and Snorkel in Cozumel. I don't want to spend all day doing one thing, what is the best way to get the most in??? Thanks in advance for your help!