Taking smaller roads to the 395 or whatever and working your way down to Vegas might be a faster way south than the Bakersfield route, unless snow or something causes issues.

Or maybe not, you can fly on the 5, and it still is somewhat angled south east.

I'm not a trucker, and am based in Southern California, so I don't know the optimal Northern California routes to places, I was just guessing why Google was sending him through Chicago.