We purchased both of our motor homes out of state and in both cases, it was a real ordeal and I probably wouldn't do it again. Dealing with California DMV (and probably many other states) is always an act of frustration. Many agents have no idea what it takes to register a motor home, especially a diesel one. You can talk to one agent and get one story and then another agent in the same office will have a different story. Our first coach was purchased in Arizona and the dealer told us that if we paid the Arizona sales tax, that when we got back to California to register and if the California taxes were less (which we knew they were) we would be reimbursed the difference. Turned out that was a total lie and we lost about $1000 on that deal. The agents at our local DMV had no clue on what smog laws our DP motor home had to conform to. It literally took months to straighten out that fubar. We had to have the motor home inspected by several different people and we received two different sets of license plates. Unbelievable.
On our second (and current) coach, we did all of our paperwork in Oregon, paid CA sales tax and registration fees and then the dealer sent all the paper to the Sacramento DMV office and they promptly lost them. When we got back to CA, we didn't received any new license plates and contacted the local DMV. They insisted we start from scratch, pay the sales taxes and registration fees again (we're talking many thousands of dollars here folks). We contacted our dealer in Oregon and they in turn contacted the Sacramento DMV. Between the two of them, they were able to find the original paper work and informed us that our duplicate taxes and registration fees would be refunded to us. Several months later and many more calls to Sacramento DMV, they finally did reimburse us.
On top of all this, the local DMV insisted that they physically inspect the motor home to insure it complied with current smog laws. The tag on the engine that proves this is located down on the front of the engine and since I have a rear radiator, I had to remove the hatch in the bathroom floor to gain access to the engine. It was quite a site seeing that, shall we say overweight, lady agent laying on the bathroom floor with her head and shoulders down in the engine compartment. At least that gave me a little payback.
It took us almost six months to get everything straightened out with our first motor home and four months for the second one.
Ron