Last I looked it up for CA, NM, AZ, and TX, you're supposed to notify local law enforcement such as sheriff that you are moving guns through the area, even as a private citizen simply on vacation. However, nobody does that and its unenforceable by any agency.
So, if you follow the letter of the law under CA rule, they're nowhere near your person, unloaded, locked in a compartment other than the glove box or center console, and ammo is locked separate from the guns, you probably won't run into any trouble. However, if you're not a dingus, you won't (a.) get pulled over or (b.) give reason for the cop to search your RV and find guns you [probably] shouldn't be transporting across state lines. Use your noggin, be a prudent and responsible person, and you won't have any problems.
RVs are common burglary sites because when people are away from them, its to fight off cabin fever and they're out for a few hours. Its why I'd recommend a locked compartment, bolted permanently out of sight to the structure of the RV. Just how many guns do you plan on taking with you?
Since its CA, you might consider selling some at the CA premium prices, and buying them new later when you settle at a lower price than your used guns. (unless you have common on-roster shit)