MRMW

Website states parking is free.

Driving. I'm from NYC--bridge and tunnel division, born and bred. After several trips to Asia, I wouldn't be afraid to drive there. The only thing stopping me in Mexico City is that it's the polar opposite of a street grid. And it's one way almost everywhere. That said, there are several ring roads and through roads. Like here in Atlanta, streets change names and there are an endless supply of 3,5,6,7 way intersections. Then there's parking, parking on the street (a no no insofar as scratched up paint goes) and secure parking (sometimes on the street if there is a 'watcher'). Clear now?

I'm with the previous poster, however, insofar as staying near the jobsite, then switching out into town for as much of the weekend as possible. In my experience clients the world over are sympathetic to leveraging work in foreign countries with as much tourism as possible, so they might even facilitate your leaving early on Friday? (I've been enabled with help ranging from consultations and advice to a car and driver and translator--everyone is proud of where they live.)

PS--I sojourned in the vicinity of Manzanillo and San Miguel de Allende via Nuevo Laredo by car for four months around the time Al Gore was thinking about inventing the internet. Driving is different. Not hard, just a little different. Like getting in the right lane to turn left. Like signaling the guy behind you it's safe to pass, like where to look for street signs. Like forgetting all the Spanish you know if you get stopped. I'm sure that by this time that there's lots of web content on the subject. If you are a good SoCal urban driver you shouldn't have a problem IMHO.