Stay at Walmart. The Mariposa truck crossing is well marked You turn right from #19. I think it is exit4. Do NOT follow the road to the border! When you get to the USA exit gates stay to the right with the trucks. After that it is a straight shot to the toll road. Do NOT stop at the customs station on your right right after you enter Mexico. Stay on the road. I take it you have a 10 year permit. You will drive through the first toll booth and come to an inspection station. Keep to the right. You will have to make a hard right to get in the right lane at that station. Some one will walk over and do a quick inspection. Stay on that toll road and you will come to what is called KM21. On the right is a big parking lot. This is where you get your tourist permit. If you need more help just ask! Stash your plants but you should be OK. Often they walk inside and in 2 seconds they are gone! If you need some sort of mechanical help and come to Kino my shop is available. I am leaving North on Sunday.
Moisheh