In CA transportation of a handgun must be done with the gun unloaded in a locked container, your glove box does not count. Long guns must be in a case designed to carry firearms, but not required to lock them, and must be unloaded during transportation. No magazines over 10 rounds, to possess is a felony. Once you are parked the firearms must not be accessible by anyone under the age of 16, but you can have them out and loaded.
No SBR's, full auto or suppressors.
CA does consider your RV your home and we do have a castle law with no duty to retreat.
Now the real question is, what county are going to be in? The coastal counties can be very unfriendly towards firearms vs the central counties being, for the most part, rather libertarian towards them.
Do not carry without a CCW issued by a county sheriff, and really, your not going to be able to get one.
You can try contacting the DOJ but they are notorious for being unresponsive and unwilling to actually answer any questions when you do get ahold of them.