Exhaustive internet research has (as usual) left me confused. I am a U.S. government employee currently posted overseas, but not military. My parents have just moved from NJ to FL, so I am in the process of changing my state residency accordingly. I will PCS back to the U.S. this summer and am currently hoping to fly into San Fransisco, buy a car, and drive it to Washington, D.C. where I will reside starting in the fall. Is anyone familiar enough with the machinations of the California DMV to know whether they provide some kind of 30-day temporary registration credential that I can use to get the car across the country? Or am I really stuck registering the car in CA and paying the taxes and registration fees?
I don’t know, but given all the complications involved, what if you shop around for a cheap one-way rental? Then buy where you’re going to live.
I agree with @texases. My wife and I found ourselves in a similar situation while in Glendale, CA about 10 years ago. My nephew wanted to buy our van that we had driven out there and we wanted another vehicle. We sold him the van and rented a U-Haul truck one way. It was cheap because they needed the truck back east. It was new, had AC and an automatic transmission.
Unless you are looking to do a cross country road trip as a vacation, why not just fly to DC?
When you buy a used car in California the owner gives you a signed title, but the plates stay on the car and if the registration is good and stays good until it expires. You could probably drive the car all the way to DC, and register it there. Ask an insurance company if they will write you liability insurance.
Beyond that, look at www.dmv.ca.gov and do your research. You called yourself “Crookedlawyer” so I assume you can figure out how to play the system.
“You called yourself “Crookedlawyer” so I assume you can figure out how to play the system.”
Don’t say more.
I agree with renting or flying. As mentioned, in CA most used cars sold to you would have a plate and a tag. You can have the paperwork, get insurance and probably be just fine. One thing is that used cars are pricier in CA (less rust, more people, etc), so another reason to buy back east.
The idea is to take a cross-country road trip vacation – otherwise I’d just fly. I was trying to avoid the added expense of a long-term rental by just buying a car I’d end up buying anyway in California; it seems that whatever I’d save by buying on the East Coast would be offset by the cost of the rental anyway. Certainly not looking to play the system – just trying to figure out how to do things correctly and the CA DMV website isn’t all that helpful for a nonresident who has no intention of residing. The numbers I’ve crunched so far on a one-way rental don’t come out all that advantageous.
What’s with your user name?
Why not find the dealer for the vehicle you might want to buy online near where your plane will land? Contact them and they will tell you what you need to know , quote a price and most likely pick you up at the airport. And really why have a screen name like that?
“What’s with your user name?”
I think he/she is one of the rarer honest ones 
Check with the Cali DMV to see what provisions they have for buying a car there and registering It permanently in another state. Also check with the DC, MD or VA DMV to see what their requirements are for buying out of state and permanently registering there. Do you know which of the 3 you will live in when you return to the States?
Maryland will require an inspection to register an out of state vehicle but you have the option of applying for a 30 day temporary tag. You will need the tile for the vehicle from California and proof of Insurance with a company operating in Maryland. D.C. and Virginia may have different rules.
A safety inspection is required for a used car, but a new car won’t nene the inspection.
I would go with a one way rental if the purpose of the trip is to see the USA. Don’t bother with maintaining a California vehicle in the East! You will regret it!
Used vehicles are specifically mentioned but getting the new vehicle titled in Maryland would require the MSO at least. No mention about titling a new car coming from another state.
From mva.maryland.gov
What should I do if I want to buy a vehicle from another state?
Buying a vehicle in Maryland can be a tricky business, so buying a vehicle from another state might seem like a gigantic task. In actuality, it’s not very different.
Follow the same procedures as you would to buy a vehicle in Maryland, making sure that you have the seller sign over the title to you. Since the vehicle is coming from another state, you will need to get a safety inspection in Maryland at a full-service MVA office.
If you don’t have tags for the vehicles, you can apply for temporary tags at an MVA office. Temporary tags are $20 and are valid for 30 days which should be enough time for you to inspect, register, and insure your vehicle
Most . . . maybe all . . . new vehicles meet California emissions requirements
Somebody correct me, if I’m wrong
MD uses Cali requirements now.
You might want to consider buying in Nevada or someplace besides California. There should be no problem getting a 30 day transit permit either place. One thing though to check on is the possible taxes. I don’t know anything about California fees but think everything is high there. Each state has a different set of fees. Colorado has a 2% of vehicle cost first year registration tax plus the sales tax. So it’ll be worth a call to the DMV or dealer to check the fees on both ends.