It is slowly rotting and needs significant repairs to get it prepared to sell to a typical home buyer for a primary residence.

I don't really want to invest in a D-class area.Tangentially, what are some of your "it's time to sell this property" red lines when it comes to the changing economic conditions of an area? 

And selling real estate is usually easier than selling a business.

Then, we would move on to another house and repeat, either keeping the former house as a rental, or selling it on a lease with option to buy arrangement.

Crime and drugs still an issue, but getting quality tenants has not been a challenge... so far so good.

I than thought it was tenants, all the "what if's"; what-if they have a fire, what-if there is a shooting, dead body, drug raid, break-in, squatters, feces art, etc etc etc.....   

They do not take into consideration the revenue from the STR business as part of the selling price.So if comps say the duplex is worth 500k, then it is worth 500k.

Donnie I'm selling that place.

Again, see question #1.Selling as-is means selling it cheap, no hassle, quick sale.

Do we sell the property and recouperate our investment?