I can second the recommendation for using a non-DMV registration service. Some are better than others. The one I used to bring my Miata in from my previous home state was terrible. Missed a digit on my odometer, came very close to screwing up the tax I owed by a factor of 10, etc. The one I used to register my 72 was awesome - in and out in less than 10 minutes.
Thinking about it, the difference was that the first was a registration service only. The other offered registration services as a value-add to their smog services. At the second one, they were busy and just wanted to get me in and out, whereas the first had time to screw stuff up.
Find a local smog + registration shop and bring them exactly what the DMV website says to bring for bringing an out-of-state vehicle into CA. Unless the DMV has somehow flagged your VIN/name/whatever, you should be able to walk out with new plates in hand. They will charge you a premium for this over whatever the DMV would charge, but at this point, I think we'll all agree it's money well spent.
Just to give an example of the type of place, this is one.
https://www.yelp.com/biz/mr-smog-and...anorama-city-2 I've never been to this place, have no affiliation, just pulled it out of a quick search. Apparently Yelp has an entire "Registration Services" category.
Best of luck!