Geographically it’s a huge country so really would benefit from having factories scattered around the country/NAFTAland. Even if some of them clustered in a preferential region (lumber in Canada, car parts in Mexico, certain foodstuff is in California) it offers some risk.
Remember when a fire in a single factory in Japan crippled the semiconductor industry world wide a few years ago?
Growing food in California should be re-thought if you ask me, given the prolonged drought conditions. At some point shipping water to California just doesn't make sense any longer. Instead of shipping the water to California, grow the food where the water is, even if the yields aren't as high. Like you said, a single crop failure in California can wipe out near 100% of the US' food production for certain fruits and vegetables or at least a very very sizable portion of it.
On the far side of these mountains you will find the humid wetlands and the wide rivers of ... Nevada. Perhaps you can try kayaking on Groom Lake someday.