On Publication 52 and getting out of the California use tax, how people use it, in my opinion, is a loophole. What the law allows is for a person who is a California resident to purchase a vehicle or a vessel that is intended for use in another state. For example it would not be unusual for somebody in California to purchase a yacht that they keep in Florida intended for use in Florida. In that case the yacht would be registered in Florida and Florida would get the taxes. The same could be true of a motorhome. The intent of the law is to allow California residents to purchase these items out of State if the intent is for them to remain out of state and be used mostly out of state. The law then goes on to tell you what you have to do in order to prove that is your intent and currently that now requires the 12 month stay out of state.
So in my opinion, if you are using this law simply to avoid paying the sales tax and you fully intend to bring the vehicle into California as soon as your 12 months expires, then technically you are violating that law. However, it would be an unprosecutable violation as even though you did not comply with the spirit of the law, you did comply with the letter of the law. So you can use this loophole to avoid California use tax.
When I purchased my Class A the sales tax was $13k. At the time the requirement was only keeping it out of state six months and I could have easily done that. But I read the law and I saw that wasn't the intent of the law, and since I myself was a government law enforcement employee at the time, I choose to pay the sales tax on the vehicle.