Greg & Heather,
My two experiences of buying motorhomes one in Indiana and one in NC.
First one I was still in the military and claimed Fl as my home of residence even though I was stationed in Va. I put Fl tags on the vehicle and paid the Florida sales tax. (so essentially skipped all the Va taxes becuase was active duty military). Was not required to go to Fl to get tags after my sales tax was paid to Fl.
Second one bought in NC after I retired and a resident of Va. I did not pay NC sales tax but had to pay Va sales tax, Va personal property tax, tag fees, and get the m/h inspected in Va. NC did give me a 30 day temporary tag to get home and do all my running around to pay my taxes etc. I did not know or was aware of a 90 day rule that would have been nice. The 30 day tag and vehicle inspection were the long poles in the tent for me. I did ask if I could pay the Va sales tax when I purchased the motorhome and the dealership was not to keen on that idea.
I'm sure California is like Va which taxes you to death, and I'm sure both places are seriously considerting taxing the air we breathe.
I will say this when I was on active duty I had all my cars tagged in Fla. I bought at least 4 cars in Va and the dealerships did all the paperwork etc too include taxes and titling like I was buying my cars in Fl. Sales tax somehow went to Fl. I was never billed later for anything from the state of Fl and they sent me tags (read did not require a trip at all to Florida) process was seamless. One thing to remember is Fl does not have a vehicle inspection program but if they did I would have been required to get that as a military person the next time I was actually in the state of Fl. So their must be a process in place to do something like you wish, the key would be getting the RV dealrship off of top dead center and figure it out.
Jeff