Tonina is my favorite of the Mayan ruins. It is in a temperate zone, not wet and steamy like Palenque. It's the highest pyramid in all Mexico, but that is a result of topography. The people of that area used an existing mountain, one that gradually rose up from the valley floor as the base for their 'pyramid'. Nevertheless, it is spectacular and overlooks a beautiful verdant valley with many "ranchitos", large farms that raise chickens, ducks, geese, and cattle. There is little signage, so it's good to bone up with a good guide book. People are allowed to climb over most of the ruins and the view from the very top is spectacular in all directions. The museum is small but full of important artifacts and information about the Mayan City states, their calendar, and politics. Tonina is the state that took down mighty Palenque.
It is a day trip from San Cristobal de las Casas, or one could find a hotel in Ocosingo, the nearest large town. Combies run from Ocosingo about every fifteen minutes to the ruins, food and restrooms are available at the site.