Found a deal on a duplex! (I think), now what?? HELP!

[Justin Brown]

So here are the stats on the property I found:

Found owner through yellow letter, asking price: 178k, near a mid-sized city in WA state

2 bed/2 bath on each side, somewhat updated and in good condition (pretty standard look with off white walls, basic carpet, etc.) New roof, carport, safe part of town near school.

Rental average approx $720 per side currently, market rate more like $850/side at least.

The owner is willing to do seller financing...so how should I move forward???

My only concern is there is a septic system! So here are my thoughts for moving forward, BP community provide feedback if you have any!

_________________________________________________________________

Get my RE agent involved and pay her cost to help draft paperwork and orchestrate financing. Offer 25k under asking price ($153) because of the septic system. I want to hook up the duplex to sewer and this is at least how much it will cost (I checked with city). Ask owner if she will seller finance for 15% down. Up the rents when I purchase to $750 for now. Anyone have any tips? This property hasn't been listed, so I'm trying to move fast (but smart).