You can dive the entire east coast of the yucatan. My son and I took a road trip last year from cancun to xcalak. We dove in akumal, tulum, mahaual, and spent three days in xcalak with xtc divers. Fun trip, we liked the road trip aspect. Didn't book in advance, as we had no set plan. Although it was a holiday week we were able to find accomodations each night, some better than others. I can recommend costa de cocos in xcalak. This may not work for you, but if you are a flexible traveler and like to explore the road less traveled then you might enjoy a trip like this. Good luck happy divin.
P.S. travelling through the peninsula felt quite safe to us and we had no issues. There were occasional road stops at checkpoints set up by the military, however these were no issue and actually made us feel safer knowing there were patrols.