Invest a some helper springs for the back of your car or truck. You can bet that California police will be watching those border areas for cars that are loaded with heavy stuff, just like they used to do with moonshine runners.
Well screw that then - we'll take the RV-6.
Now gotta figure out how much 2,000 rounds of 5.56, 2,000 rounds of 45, 2,000 rounds of 9 weighs...
Oughtta be no problem if I leave the wife home!