Check the official tourism websites of the specific Mexican state you are visiting; they often provide free "Guías Turísticas" in PDF format that include street maps.
Physical maps or downloaded PDFs don't fail in areas with poor cellular reception. guia roji 2020 pdf descargar 8 pages pdf gratis
Go to a reputable online map service, select the "Area of Interest," and use the print function to save it as a PDF. Check the official tourism websites of the specific