Is this a decent deal for a Southern California fourplex?

[Logan Allec]

Unit Type: Fourplex (two detached studios + duplex)
Year Built: 1965
Building Size: 1,700 sq. ft.
Price: $440,000
Current Rents: $3,755 ($1,075 + $1,005 + $900 + $675 + $100 storage).  The $675 unit is below market...currently an elderly widow on fixed income lives there, and the landlord has never increased the rent on her.  I would intend on owner-occupying that unit for a year and then renting it out at market rent ($850) to boost total rents to $3,930.  There is also some room for upside on the $900 unit as the current property manager currently lives there getting reduced rents, but I don't want to get too fluffy with my assumptions.
Owner: older lady who has owned the property for 20+ years and wants to retire/cash out.
Tenants: all (except the property manager) occupied by long-term, older tenants.  There is no rent control.  
Area: this is not war zone property.  Median household income for the ZIP code is $115,000, which is much higher than both the state and county averages.  Although rural, it is not too far in the middle of nowhere.  Many people in this area commute an hour to Downtown Los Angeles everyday.
Condition: I drove by.  Looks like the live-in property manager has done a good job keeping things in shape.

Thoughts, anyone?  I'm tired of tire kicking and just reading about real estate.  I want to do something. Last week I was almost ready to just give up on finding an FHA-eligible fourplex in SoCal and wave the white flag and go turnkey in Memphis just for the sake of doing something.  And at 3.5% down and throw in some closing costs, I'm looking at a mere $20,000 outlay.  I've done more foolish things with $20,000 in my short life, so I'm inclined to just pull the trigger on this one.

I'm all ears, people!

[Amanda Hensley]

Do you *really* need a place to live, or are you planning to owner occupy the under market unit in order to be able to raise the rent to market?

I personally would feel badly kicking out an elderly person on a fixed income just so I could raise the rent to market...  You are not doing too badly on this deal with the rent on that unit where it is....