Okay, so I have a perspective 6-unit property I may buy. It has been on the market for a while (9 months) and through communication with the seller he seems ready to get out and move on.  The property is in fairly good repair with a new roof 5 years ago. The area is surrounded by other multi-unit rentals of equal to worse condition, so I expect competition to be stiff and may not be able to raise rents as much as I would like.  The rents are currently a little below mkt for the area. I have a potential partner, but I believe he would be better suited for a different property. That said, I am still interested in the property and believe I may be able to get it with some creative financing. 

He is willing to do a seller finance deal so I am hoping he will be open to another proposal. I plan to offer his ask if he would take a note for 25-30%, in hopes that I could get financed traditionally. If I am able to acquire the property this way, I plan to use the cash flow to rehab the units as they come available and make the exterior more aesthetic. I think about $35-40,000 should do if I do most of the work myself.  A conservative estimate puts me at about $12,000 per yr if the seller is willing to forgo payments and just take a bubble when I refinance and take out the equity of the added value. Assuming I could borrow enough.

He is asking 450,000 for the property and I believe that after the improvements I can increase the cash flow by approximately 30-35%. I estimate the value of the property would increase to around $660,000 give or take. 

All excess cash would go into mortgage payments, paying the sellers note, and or improvements to bring in more cash and increase equity.

So, I know I didn't give you too much info. But is this even doable?  What considerations should I take into account? What might impede my strategy? The risks? Does anyone have experience with this? How, did it work out?

Thanks ahead of time for the feedback.