Pure beginner first offer.. help!

[Anthony Ghotti]

Hello bp. So this is my first ever offer on any type property. I came across a window sign "for sale by owner". I remember seeing this property on the market and checked up realtytrac. And sure enough there it was estomates at 288k.. they were asking 325k. So the idea I have it to go at this with an owner financing deal. I checked county records and it show's 100% owned by the owner. So here are my numbers.. 

SFR built in 52' house size 1296sqft. Lot size 6500sqft . 4bd 2.5bath .

Asking 325k  estimated 288k

Rental median for 4bd in this town is 1600mnthly 

If I rent the room's individually I'm looking at 2000 mnthly

Vacancy $128 or $160

Insurance  $95 for either 

Maint. $160 or $200

Taxes $47 for either

Management $160 or $200

Total expense $590 or $702

Ammoritized at 30yrs "OCB" 

$916 monthly.

5yesr balloon remaining 267,038

10yr balloon $213,256

Remodel info

New appliancestors , hardwood floors, paint, double pane windows , kitchen and bathroom

Roof is 8years old 

Neighborhood grade I would say C

Property overall look outside C+ or B-

So the first numbers are renting to a family only  and the second set is renting rooms individually. In my area there are 2 hospitals that get interns and nurses from other states , there are 2 prisons for "co's" to work and there has also been teacher who look for studios or 1 bedrooms here too. 

I assume the owner financing options. Would be available because this house is being listed at above estimated value. And it never sold. It currently sits vacant. And only a for sale sign has been on it ...I don't think they want to deal with renting. All input is welcome and please help me better underating these numbers. I see I would be in the red renting to a single family but if I don't include management and manage myself for as long as I have it then I would be in the green about $150+ thanks for your time.