We are thinking about driving our car into Mexico. Any advice on auto insurance?

Although Mexican auto insurance in valid in the US, they don’t return the favor and your insurance will be void in Mexico. You will have to get Mexican insurance coverage, available at many of the border crossings for you time there. Also, if you are stopped, do NOT hand your driver’s license to the local police or you will have to pay them a bribe to get it back. Hold it to the inside of the window glass so they can read it, but don’t let them get their hands on it.

American car insurance has no value in Mexico .You need to have a separate policy. Fortunately there are stores located along the border that sell Mexican insurance policies. AAA also sell it
You can’t take a rental car into Mexico.
If your car isn’t paid for and you don’t have a free and clear title for it, then you will need permission from the leinholder to take the car into Mexico .Something about cars disappearing in Mexico and the Mexican government not exactly being 100%cooperative in helping the rightful owners recover their vehicles.
Use bank ATM machines for getting cash .
Carry a lot of small denominations in the event that you need to negotiate a ticket with the local cops .They tend to be a bit hesitant when it comes to making change
Another good reason to carry small denominations is that haggling for goods and services is part of the culture and having small denominations just gives you an edge -up in that process.
Lastly if you don’t speak Spanish and you want to do a crash course in it , get a book on Latin American Spanish-not Castillian Spanish.
have fun

Wow ! There are some really wrong answers on here.

Believe or not, most standard insurance companies actually allow you to be covered in Mexico. It is an endorsement, so it will cost a little extra. They will usually cover you within 75 miles of the border. Call your agent and ask.