We went on an excursion to Rio Secreto during our Oasis of the Seas cruise to Cozumel and it was really amazing. It was about an hour traversing water in a cenote (about a mile and a half). The water wasn’t too deep, but there were several areas that were very, very, very tight. You can read the detailed account here.
We did an off-road tour in a dune buggy and it was a lot of fun. We kind of “crashed” on one of the big jumps, but fortunately did not get hurt too bad. There was also a jump into the Jade Cavern cenote partway through the excursion. As you can probably tell from the video, the dune buggy ride is very, very bumpy.