Driving in Mexico

I rented a car recently, figuring we'd be traveling to some out of the way places.
The route was Zacatecas to Zamora, Zamora to Morelia, Morelia to Uruapan and from Uruapan to Paricutin, Zirahuen, Patzcuaro, and Tzaracua, all 4 places within an hour's drive from Uruapan.

First, the toll roads cut driving time by as much as 75%.
Second, tolls are high; I spent about $75 on tolls on this jaunt, plus the same amount on gas.
I could have saved about 75% of the expense by renting the car in Morelia and taking the bus from Zacatecas to Zamora and then Morelia and then dropping the car off in Morelia on the return trip. It would have cost me about 8 hours additional travel time, but I have lots of that.

The road signs are pretty good from city to city, but watch out, once you get into the city, signage may be missing, hidden, or point to intermediate locations. I found it pretty reliable to ask at the toll booths for directions to the next turn. Also, read every sign, even the ones that face cross streets. And in one case, the sign was 100 feet past the turnoff.

So, if you are adventurous enough to explore Mexico by car. List all the towns you are going to pass through because they may be the only signs you see for a long time. Get directions from someone who knows the route including landmarks. If you think you are lost, you probably are. Stop and get directions using a detailed map and sign language if necessary.