-- Last Updated: Jan-24-13 3:40 PM EST --
If you are crossing into Baja or Sonora, you just do it.
Some places you might pay a business to watch your kayak on your car in their yard if you are leaving it unattended. Usually this is not a problem, but there are problems with crime that do happen, unfortunately.
You do want to be careful where you stay, and only drive in the daytime in Mexico. Stay around other groups of campers. Be prepared to be stopped and searched on outlying roads. This can be quite stressful as the Federal police look quite intimidating but seem to be honest. Local police or those pretending to be police can be a different story. Car jackings and robbery was very common a couple of years ago, we don't hear so much lately, but most folks have stopped going down.