Pros: hit a reasonably good wind gap through the Isthmus, buffeted only a little by sidewinds that died down in the afternoon. Lucky. And that same day was flagged down on the road by a WarmShowers host (warmshowers.org, CouchSurfing for touring cyclists), then welcomed into a home for the night. Anyone passing through Zanatepec should look up Rodrigo’s and Lupita’s house, just follow the signs literally painted onto the highway or ask anyone in town.
Cons: struck by first bout of sickness just before crossing the isthmus, but luckily only spent one day emptying my guts everywhere. After witnessing one such episode, a kind woman, Margarita, at a comedor taught me the local word for soup (caldo) and let me crash there for the afternoon and night. Thankful.
Mountainous treetops to dry lowlands, where shade has even higher value. Note background windmills- a cautionary sign for cyclists, and even drivers here. Winds sometimes blow strongly enough to toss over tractor-trailers.
Entering Chiapas sees an immediate shift in road graffiti, nearly all taking on a religious message. San Cristobal de las Casas sits up at 7200′, so getting there involves a roughly 7000′ climb from the lowlands to the surrounding mountains. There are two routes to choose from, the new toll road that does the climb in ~40km, or the old highway that winds through small indigenous villages for a slightly longer 65km. I took the old highway, and even starting early in the morning, didn’t get to San Cristobal until late afternoon. A good climb, great for the appetite!