Based in Palenque rather than in San Cristóbal, which shortens the Usumacinta trips considerably — Yaxchilán and Bonampak from here is a long day rather than a brutal one.
They have been running Chiapas, Tabasco and Campeche itineraries for twenty-five years and sell the waterfall circuit at Agua Azul and Misol-Ha, the ruins, and transfers down to the Guatemalan border crossings at Frontera Corozal and La Técnica.
No street address is published, so this is pinned on the town.