Typically if a duplex is in an area with lots of other rental properties it may sell lower than an area of single family homes with mostly owner occupant homes, so location may also be the driver behind the value differential. 

  ( if it was not obvious the line had been replaced in the recent past or was not PVC.).Its one thing I see many turn key buyers miss in their home inspections is a sewer scope.. out in our market every realtor first thing they do is recommend a sewer scope I even have them do them on my new construction homes..  

If it's a smaller bank/lender, they MAY be willing to work with you and sell you the note, you could then work with her to get a Deed in Lieu on a Cash For Keys deal.  

In your area look for the potential economic drivers that are operational today that may attract outside investment.

Some tenants will do so if they have extra incentive.... such as cash for keys.

Hello BP folks,I'm shopping in LA and this turn key triplex came up.

Practice makes perfect and patience is the key to finding the right deal.

Constant evolution and education is the key! 

Getting air flow is key to remove any condensation.  

Also the owner has offered the tenant cash for key but they aren't willing to move.