Another potential bureaucratic gotcha to be aware of is the Mexican government's FMM, or Forma Migratoria Multiple. You're ostensibly supposed to get one of these tourist forms upon crossing the border if you are travelling beyond around 20km into Mexico. Here's what the
US State Department says about it:
"If you enter Mexico by land and plan to travel beyond the immediate border
area (approximately 20 kilometers into Mexico) you must stop at an INM
office at the port of entry to obtain an entry permit (Forma Migratoria
Multiple or FMM), even if not explicitly directed to do so by Mexican
officials. You must present a valid passport in order to receive the entry
permit. You may be asked to present your passport and valid entry permit at
immigration checkpoints on your route of travel."
We tried to get ours online, for which the Mexican government has a website. But it was pretty painful, and because I neglected to print out the payment receipts it turned out to be useless. I went into the customs office just past the Tijuana crossing, and ended up paying on site for brand new FMM forms instead. $50 each person, so not a trivial amount of money.
In the end though, nobody ever looked at them. Even at the many roadside checkpoints manned by well-armed 19-year-olds,l they did not ask to see the FMM. So: supposedly required, but you might end up getting away with it if you chanced not getting them...
I ended up going with Lewis & Lewis, which seemed to have a good reputation, covered cars in the high-5-digit value range, and allowed me to both shop and buy online. I bought a Baja+Sonora 1-month policy, and printed out the result right away (they sent a copy in the mail later, as well).
