Might just need a little work on the outside and there is potential for adding central air as it is currently set up with window units (very common in the midwest area I am currently looking). 

Other than it being smaller, painting a house between tenants is going to cost the same, a new roof will cost the same, a new air conditioner, hot water heater, furnace will be the same cost etc.For instance, it costs us about $1,000-$1,500 plus a months rent as a leasing fee. each time we change tenants, by the time we paint, do landscaping, repair damage, change locks, patch holes, paint walls that need to be painted get a make ready clean. 

Might not be awful to buy it an put it on Air BnB, might draw some tenants at a marked-up rental rate.

We had the cheapest beer in town and a window air conditioner. 

We aired it out for days, sanded down the wood floors and resurfaced them, cleaned and painted the walls, and used odorxit AQM, and managed to clear the stench. 

While it does present an issue in the summer months, doing a short term rental or Air B/B may be a possibility for the summer depending on the area. 

We have an excellent regional hospital - but children with severe injuries or issues are usually transported by air to Children's Hospital in Denver.

Has anyone used mini split systems in apartments, and if so, have tenants been happy? I have one and two bedroom units around 700’ each. These are located in Oklahoma so there is potential for occasional temps in sing...

Similarly, newer buildings might only need cosmetic touch ups to bring them up to modern standards.This isn’t single-family residence where you can estimate an ARV (good points by @Michael Le), stick your thumb in the air and estimate.

What is density allowance with air rights?