You’re not actually going to start at Nentón – instead, you’ll probably arrive from the Interamerican Highway or maybe from Mexico via the Carmen Xhán-Gracias a Dios border crossing. Either way, Nentón is a good place to fill up on water and foodstuffs before you find yourself in the shit. Just about 2 km north of Nentón say goodbye to the tarmac and turn onto the unpaved road going northwest. Enjoy the next 11 km of off-tarmac bliss – just try to keep your speed under control. Grab a cold drink in the small town of Chacaj and then continue to the end of the main street where you encounter a (probably) closed gate. Turn right here and continue for about 4 km where you will enter a small community where the locals will probably take interest at the sound of your approach and gather around the large tree in the, uh, town square. Here, if your Spanish is limited, the question, “Cenotes?” will be met with a pointed finger to continue onward.
A short ways ahead, you will come to a chain across the road. The toll is Q30 (about USD4). Andrés, the toll collector, is very helpful if you find yourself in a pinch and he even has a little English from four years of working on roofs in Florida, USA. From here you first notice some attempts to patch the road but soon all pretenses of your toll supporting road maintenance are off. The slope increases and the road degrades as you near the crown of the hill. There are two particularly bad stretches – steep and rocky – and then things tighten up for the final hundred or so meters approach to the further and larger of the two cenotes. If you arrive during the workweek or in the late afternoon, you’ll probably have the place entirely to yourself. So why not go for a skinny dip in the cool water before setting up camp back under the trees where ground is softer?
The route map (here) gets you close but there’s still another kilometer or so where Google drops off.