Costa Maya is beautiful but very small and basically just one beachfront with some restaurants and souvenir shops. You may want to see the Chacchoben ruins, they ARE realy beautiful and unique...
Cozumel...sailing and snorkeling the cozumel reefs...a dream
Zip-Line...take note of lots of little stairs to climb on a tree at 20-30ft high tree base from each tree to each tree, tour is great, not too much exercise, also good for younger participants...but there is no 2nd security line
Up to you, have nice vacations!! any questions do not hesitate to ask!