4 Plex with possiblity of 5 need creative financing idea

I am looking at a 4 plex that could possibly be a 5 plex.  Two units are currently being rented one for $600 one for $750.  The other units need to be completed.  The repairs that need to be done would be around $2000 to finish the other units.  The owners realtor is asking $280,000 for the property which would be what it could potentially sell for or higher once it is completed.  The owner is willing to negotiate with us on us buying it at a lower price.  She still has a mortgage on the property and I cannot get a traditional loan right now.  Her payments are currently $800 per month.  I need some advice for creative financing on this property, I currently live in Iowa so anything I would do needs to comply with our laws here.  I have heard about a land contract, would this potentially work or am I thinking about that wrong?