Mostly by car or bus. The cities that have it, such as Mexico City, Guadalajara or Monterrey, have an underground metro system. For inter-city transport, light rail can be used. For inter-state transport, car or bus is most usually used as Mexico has an interstate highway system much like the US'. However "cheap airlines" and some railroad can be used. Whenever available, ferries can be found.
By moving from place to place
Yes but they need to get visa
People would often travel to Mexico in caravans. Caravans are groups of people going to a place in a group. They did this so that bandits or robbers would most likely notice the large group and not bother them.
Yes, of course. Mexico is a popular tourist destination; the second largest in the Americas (after the United States).
I do not know except is it cheap. But you can go farther south in central America and in the caribbean just as cheap. Mexico is filthy and unsafe. Travel elsewhere!
Yes, individuals with a green card can travel to Mexico.
It was easier for people to travel and trade on, from Missouri to New Mexico.
No, a child cannot travel to Mexico without a passport.
Yes, Brazilians need a visa to travel to Mexico.
Yes, Peruvians need a visa to travel to Mexico.
Yes, babies need a passport to travel to Mexico.
Yes, babies need passports to travel to Mexico.