It is a huge pain in the ass. I just went through this again getting my car from Kentucky. They didn't sell temp tags there, Ohio wanted the title to issue a temp tag. So we pulled plates from another car and drove it back because the owner would not lend us his tags for a few days.
It did appear that the people who did the out of state inspection and the Kentucky DMV seemed to think of it as normal to use old plates or different plates as long as you had proper documentation. With that said - I don't know what law enforcement would have to say between here and Cali.