Bus-About Mexico: 16 Days from Mexico City to Cancun

Days 1-2: No Plans

San Cristobal de Las Casa is not the type of place you travel to with an itinerary, because it's more about the experience than going to see any one thing in particular. The vegan/hippy capital of Mexico has a lot to offer from food, artwork, streetart, alcohol tastings, markets, movie screenings, and more. Rather than suggest any one thing, the best thing to do is ask for recommendations. That being said, there are a few points of interest for folks who need more structure:

• Canyon del Sumidero can reach up to a kilometer in height, and stretches for 13km. Best of all, you can take a boat down the river as part of a day trip.
• San Juan de Chamula is a small, unassuming, and relatively poor town with an interesting secret: it's citizens never fully adopted Christianity. While the Spaniards built a church in town, the rituals that take place inisde are not your your average Sunday mass. Just be careful with photographs - the locals will confiscate your camera if they catch you taking any.
• Much like the north of Mexico has tequila, Chiapas (the southernmost state) has pox (posche) and San Cristobal has a handful of distilleries and tasting rooms - I suggest asking around for a guided distillery/art walk.
• If you'd rather avoid bus uncertainty, you can take northward day tours from san Cristobal to Palenque, Misol-ha, and Agua Azul (the next destination). However, note that on your way back you'll be going south, away from the Yucatan (the next region in this itinerary), so it makes more sense for bus-folk to have a dedicated stop in Palenque rather than bounce back to San Cristobal.

Departure

Chiapas is one of the few places in Mexico where taking a bus comes with some risk, though it's moreso to your schedule than your safety. There are numerous communist/separatist villages in the mountains of Chiapas, and the bus monopolies of the state are frequent targets of theirs. While travelling through, the bus ahead of mine was pulled over, forcefuly disembarked and set on fire in protest (the passengers were safe and were sent onwards by local vans).