Im coming to Riviera Maya in October with my family and I would at least like to do one excursion. I have been to excaret and since my son is 2 I dont know if that would be too much for him. If you have any ideas please let me know. Thank you!! Oh and I LOVE this website!!
We took our little girl to Xcaret when she was 2 and she enjoyed it. You can rent heavy duty strollers there so dont worry too much about the walking. Lots of animals to see which I am sure your little boy would love and play areas for kids of all ages. Another possibility is Crococun close to Puerto Morelos, an interactive zoo with monkeys, snakes, deer, crocodiles etc
I agree with Steve, Xcaret is a good place for small kids. My son was 2 when he swam the underground river for the first time. It's nice as the paths are wide and well maintained, great for a stroller. Totally agree with Steve on Crococun too, we got at least once a year, great little zoo. The Wet N Wild waterpark has a nice kid's area too for another option.