Need advice in structuring a deal - double duplex, elderly owner

[Tandi H.]

I'd appreciate advice in how to structure this specific kind of deal:

- Current owner is a neighbor/friend, who is 75 and wanting to get out of two duplexes in the near future (4-12 months).  My husband has done handyman work for her and says the properties are in decent but not upgraded condition.  She's owned them for 25 years and they are her retirement asset.  1950's construction.

- The two properties are next-door to each other.  Each duplex unit is a 2/1.  So total four units of 2/1.

- Properties are a couple blocks away from our house. We own our home, a SFH, and a duplex, all in the neighborhood.

- They were appraised at $260k each about a year ago. She said she could be flexible on price though for the right people.

- She says they are cash flowing (three units, as she occupies one) about $24k a year.  A 2/1 in a duplex in our neighborhood could rent for $900-1200/mo depending on size, condition, yard, etc.  

- Owner lives in one unit, and would like to stay in it till her death - when that happens is of course a big question mark.

- She's had a lot of people after her to sell them, but she likes us a lot. She wants to sell them to people who she likes and who will keep up the properties.

- She wants to enjoy things now as who knows how much time she has left.

- She's going to spend the next few months selling a bunch of stuff stored in the garages before she considers selling the properties. So the timeline to start the deal is a few months off at least.

Questions: 

1. I was recently laid off, so I'm not sure what kind of loan we could get.  Maybe if we did a large enough down payment we could still get a loan, based on my husbands income (which fluctuates) and our other rental income?  Or based on the income of the properties themselves?
2. How would you structure an owner financed deal for this situation? Currently I think we could do a down payment of 100-150k (upper end would be a stretch). Another idea is we could potentially sell our SFH house, which might net about 80-90k. I think she would take a partial cash offer, if we could pay off the rest in a short amount of time. I don't know, maybe if we could pay it off in 5 years?
3. How does her indefinite occupancy play into the deal?  

I would like to give her several options to work with.