If I'm reading the location right from the article, Riviera Maya is right across the channel from Cozumel's island. There are boats you can take over to the main land now, and I'll about guarantee they will offer shore excursions to this place. Time will the biggest issue. Most stops at Cozumel are only like 8 hours or less. If you figure an hour boat ride each way plus leaving some time for delays, you probably are only going to get like 4-5 hours there.