I have been in literally hundreds of these asset class homes over the years.. and these folks just do not have the same amount of possessions as many do.. because they do move so frequently they don't collect stuff. so in many cases they can pick up and move in a matter of hours...

Try, possession prior to closing, rent paid, then close on day 91.

How can she owner finance a deal in which she does not possess the title and deed to the property?

To take possession of the actual property is a process though. 

I presume you want the property and the benefits that come with it (possession, rent, cash flow, appreciation, tax befits, equity and title).

The owner is in possession of several properties and she would love for me to help her get rid of them.

I'd give non-renewal notice, the day you take possession with proper notice period so basically your looking at prior to the 1st of the month and a 30 day wait.

We have some strange landlord/tenant statutes, including some still on the books that address sharecropping.Like Timothy we use a 3 day Pay or Quit notice.ARTICLE 3 - DISPOSSESSORY PROCEEDINGS § 44-7-50 - Demand for possession; procedure upon a tenant's refusal; concurrent issuance of federal lease termination noticeO.C.G.A. 44-7-50 (2010) 44-7-50.

So think about that for a second; lawsuit is filed next year and your plan to exit the CA market is now on hold indefinitely bc you can't sell anything, you can't borrow from anyone, and every possession you own personally has a lien against it. 

One question that needs to be addressed is that according to your state laws, have you given possession to the tenant by signing the lease?