I've even seen similar sized units go for $1000 a month for the 3BR unit.

To an insurance company, that is off the charts.

He offers any loan size and type, at 5% interest.

If all units are the same size 1/4 of your $600k sale, or $150k of the proceeds would allocate toward a 121 primary residene exclusion (assuming you owned and occupied it for at least 2 years) and be tax freeThe other $450k would qualify for a 1031 exchange. 

3) What does this property offer in terms of location, size, amenities etc.?

Evaluate locations based on the ten years preceding the COVID times compared to the current inflation rate (>5%).Population Size - Greater than 1 million.

It's helpful....One of the most important things to know is the age of the house and major systems (HVAC, Roof, plumbing, etc) and then the size of the property. 

What is the loan size? 

@Hayden Wright What size?

So the property isn't making me money right now.If I were to sell I'd incur a decent sized tax bill.