Your questions indicate, to me at least, that you are unsure of many things that lie ahead and that you should do a lot of research. You must learn about all the documents Mexico requires to allow you and your car in. Any omission will be difficult to overcome once there. Research how and when to drive, what areas are safe and which areas to avoid.
And then there is this:
"Travel Warnings are issued when long-term, protracted conditions that make a country dangerous or unstable lead the State Department to recommend that Americans avoid or consider the risk of travel to that country. A Travel Warning is also issued when the U.S. Government's ability to assist American citizens is constrained due to the closure of an embassy or consulate or because of a drawdown of its staff. The countries listed below meet those criteria.
Saudi Arabia 07/25/2013
Mali 07/18/2013
Yemen 07/16/2013
Niger 07/15/2013
Mexico 07/12/2013..."
You will want to see what your country's position is.
I like it there, it's a fascinating country. But it's changed drastically in the last several years and requires preparation and care that I didn't find necessary twenty years ago. Let us know how it goes.