How does he even know the route of the Regalo truck? Did he tail the truck?
I wonder which highway it was where the whole setup took place. From the water compass, the truck is heading south-ish. That billboard which Mike parked his car behind, as well as the hose-ropeline setup, is of something Oasis Motor Court (with a "Next Exit" graphic that looks more like a freeway map marker).
There was a green highway sign that shows how far to the next few cities, like what you see on a normal freeway. It read:
Socorro .......... 14
Las Cruces ....161
El Paso ........ 207