No way, I can drive to Arizona, even in the winter most of the time.
Under no circumstances do I ever, EVER attempt to drive between the Bay Area and Colorado. The last time I tried that, I had to detour through Bakersfield... BAKERSFIELD, and then on to, naturally, Arizona, to get back. (Once I've gone that far out of my way, why risk I-70?) Never ever again.
I'm torn between Wong's very compelling argument up there, and the allure of the Bay Area (although... Stanford? Eh...)
But if we're deciding on mobility, Arizona wins for us, hands down (flights too - cheap cheap to Phoenix). Not my fault your city doesn't merit a southerly interstate connection.