I have HEARD some pretty bad things, but never experienced any.
I would be very wary...... probably just buy the plane ticket if it were me :-)
But I DO WANT to go to mex, and travel the coast, there are more miles of empty uncrowded surf there than nearly anywhere in Central/N. America.... but that is a different kind of trip all together(based on fun!).
If I were you I would be dreading the actual drive more than dealing with any locals. The police will want your $, and will most likely have to be bargained with.....
smuggle a pistol on the journey.