Sorry if I posted this in the wrong section, I wasn't sure where to put it.

I am hoping to buy a truck and camper combo. The guy has the titles and they were signed over, but he never transferred them to his name. The plates and titles are from Oregon and we are in California. Will I be able to transfer the title to my name? What steps would I have to take to do so in this situation? I need legitimate titles so that I can comfortably travel. Is there any way to check if back taxes are owed? I'm willing to pay them with a discount from the seller to the purchase price to make up for it to speed things along. Thanks for any help!