Over the past week or so I have had quite a few emails back and forth with people who appear to be the authorities in Mexico on the subject of how much a vehicle can legally weigh when entering Mexico...
If you boondock a lot I'd get four 6 volt batteries. If you go to RV parks then a single 12 volt will do. We mostly go to RV parks but I've boondocked with a single 12 volt but do run the genny.