The US State Department recommends all road travel in Mexico be completed in the morning or early afternoon to avoid complications and dangers (and that mostly means poor roads, wandering livestock, cars without lights, and of course IF there are any criminals they love to operate under cover of darkness).
Crossing the border: as this blog from just last month states, crossing the border is NOT like a scene from Escape From New York, and is reasonably hassle-free.
Driving conditions and safety I'll leave to others who've driven it to respond. Very curious to hear what they say myself.
Phil over 6 years ago