One of the most important factor is missing: market rent

Not knowing the city and area, one can only speculate.

1. How much is the market rent? If you're new to the area, count in 10% discount of what you hear, just to be realistic. (Probably not much of appreciation to talk about with ~5 years. Maybe able to sell to homeowner later.)

2. The asking price is probably just a start for negotiation. You should look at the condition, best have a property manager/general contractor to go with you and tell you which specific repair will cost, and total cost.

3. Check zillow.com or redfin.com about recent sales of similar condition. Recent means 3-6 months. There is probably some room for negotiation, especially if you're cash offer w/o financing, w/o inspection contingency, w/o appraisal. But this doesn't mean that you don't do inspection. It just means you've done such before making an offer, either by you, your inepector/contractor/PM. (Assessment is only for tax purpose, not worthy of even considering when buying.)

4. What is crime rate in the area? Would you manage it yourself, or hire a PM? Are you or your PM comfortable managing this area. I know people bought house for 1K, and get great rent, and the tenant seems OK. But is it for you?

Hope this helps.