Legal Question in Real Estate Law in California

There is nothing legally prohibiting what you propose to do. I have to wonder, however, what idiot is willing to buy a building without title insurance and an escrow. I also have to wonder if you really have thought through your legal exposure if the buyer defaults on the note, and are you sure you know and are prepared to comply with all the seller's obligations in a real property sale? If you don't and the buyer finds anything wrong with the property or just gets buyer's remorse, you could be in for a world of trouble. If you already have a buyer and agreed terms, you can probably find a Realtor who will handle the transaction for much less than their full usual commission since they will have no marketing expense. It would probably be money well spent.

You can find out if there is a due on sale clause by getting a copy of the deed of trust (which you erroneously refer to as a "mortgage') from the county recorder's office. That will tell you whether there is a due on sale clause.

I also agree with Mr. McCormick about the title insurance and use of an escrow. The only suggestion that I have to use in lieu of title and escrow is to use an attorney for a "sit down closing," which you would have to pay hourly, but you will not have a policy of title insurance.