Once comfortable, there may be some local maps from Pemex stations that will show greater detail and be more recent depending on the area. Detailed topographical camping and hiking maps are harder to obtain but are available in some areas. There are also numerous website locations with varying levels of products and services that may have what you are looking for. Local Transport Car ownership is something North Americans take for granted. Only a small percentage of the people in the Mayan world can afford cars and most either walk, ride a bike or take a bus.
Public busses are crowded, dirty, cheap and can also be fun for mingling with the locals.
Most of the major cities in the region have bus services that run through the day in and out of the major metropolitan centers and, in some cases, the outlying areas. As a traveler, I have been on buses for fun, but would not like to depend on them to get someplace I had to be. Hours can be sporadic with changes in service without warning. Travel during the day around tourist areas is almost guaranteed. There are designated stops but busses will stop almost anywhere as long as you flag down the driver.