To the OP, contrary to a lot of the info you have seen on here, California registration fees have actually mostly gone down. In 2011 the VLF was decreased to .65 percent of the value. I see you bought your motorhome this year which may explain why the fees are so high, but in order to get to where you're at you would have had to pay more than $100k for your motorhome. For a non-commercial vehicle (including a motorhome) your registration consists of some fixed fees of about $90 depending on your county and any added on fees and then .65 percent of the value, which decreases each year. So since you just bought your used motorhome this year, if you paid $100k for it, your registration should be $90 plus .65 percent of $100k which is $650. So that would be $740 total. So for what you're reporting your purchase price was over $100k?
I'm looking at my reg form right now and my VLF fee is $172. So at .65 percent that means I'm being billed on an assessed value of about $27,000. Now I paid well over $100k for mine, but I bought it new and per the DMV website your assessed value goes down for 11 years after purchase and then becomes fixed. That's why my 2015 Reg was the same as 2016. I have no idea what you paid for your motorhome, but I see DP's about the age of our motorhomes all the time in the under $50k range. I doubt I could get $50k is I tried to sell mine now, and it only has about 35000 miles on it.