Tackling An OFF MARKET 4-Plex

[Nick Love]

Good Afternoon Everyone, 

I have a seller that is willing to sell a 4-plex to me in an amazing neighborhood of Dallas, TX (down the street from greenville). He sent me over the rent roll (one vacant unit, but if it was rented the total rent $4395/month, market is 4725/month) and he has told me that there is about $200,000 of debt left on the property through a community bank loan.

The seller is open to a owner finance situation and I thought it might be a good idea to move into the vacant unit and down the road get a loan on the property as owner-occupied, but here are my questions.

What is the best way to structure the Owner Finance loan as far as interest rate and balloon?

How to calculate the maximum amount to pay for the property?