To be honest I am sort of enjoying this travelogue through a part of Mexico I've never gotten around to visit. I only made it as far as Oaxaca City.
When these migrants get to Tehuantepec by tomorrow, they'll have to show whether they're turning north on the 190 toward Oaxaca City. From there is a toll road toward Puebla and Mexico City, which is the fast way for them to go up the east coast if they're trying for the 1000 mile trip to south Texas, rather than the over 2000 mile trip up the west coast to the US border in California and Arizona. Maybe they have some secret plan to catch high speed buses in Oaxaca city. If I were trying to interrupt this thing, I'd be looking there.
This is tremendously disruptive for Mexico, and soon they'll be getting to the less revolutionary more conventional areas where the local governments might be more hostile.