Especially on a one-way into CA, they will likely give you a vehicle with CA plates due to California's funky law. Just ask the person at the counter.

On my last Avis rental (two weeks ago) I booked a full size, but really wanted an SUV. However they were too expensive to book. When I arrived at the counter, I was chatting up the CSR. She asked if I wanted to upgrade to an SUV. I asked how much? She said, $50 per day. I told her that was too much for me (especially since my full size rate was $15 per day). She said, "OK, well I don't have any full size cars anyway, so how about a free upgrade to an SUV?" LOL Of course she tried to give me a Dodge Journey first. I asked if she had an Escape, to which she replied, "of course!" Nice 2014 Escape with leather, heated seats, backup camera, etc.