The slow-travel philosophy
A month in Mexico is best spent in 2–3 bases of about 10 days each. You get a feel for daily life, eat at the same taquería twice, and stop being a tourist.
Week 1: Mexico City
Rent an Airbnb in Roma or Condesa. Use the metro. Eat at the markets. Take day trips to Teotihuacán, Tepoztlán and Puebla.
Week 2: Oaxaca
Fly to Oaxaca. Stay in centro or Jalatlaco. Do mezcal villages, Hierve el Agua, the coast (Mazunte/Zipolite) for 2 nights.
Week 3: Chiapas
Fly Oaxaca → Tuxtla. Base in San Cristóbal de las Casas. Day trips to Sumidero Canyon, Chamula and Palenque.
Week 4: Yucatán + coast
Fly Tuxtla → Mérida. End the month with a few beach days in Tulum or Holbox before flying home from Cancún.
Cost
Slow travel in Mexico for one month: $1,500–2,800 per person if you stay in Airbnbs and eat at neighbourhood spots.