Stationed here because of the Air Force, but will be moving on to somewhere else in about two years. 

@Jessica Jay-Maleski, since I'm sure air conditioning is a must in your area, I might consider upgrading the units to have ductless mini-split air conditioning systems.

Tenant erected a 12 x 12 outdoor extendable living accommodation shed in the backyard without any permission installed permanent tiles, ran wiring in the shed for lighting, fans, for electrical devices and also for air conditioning.

My property was on the market two weeks and was able to get it rented by an Air force couple..

Baltimore Air BnB is under attack....the new bill that goes into law shortly, essentially bans short term rentals in homes that you don't currently live in.

I would have central air/heating repaired.

Is it a window AC unit or is it a Central air unit?

A high tech air filtration unit, a newer heat/ air unit?

I now understand you were looking for the things that normal due diligence might miss.I had a person who bought a property that was in a larger town and there was the air space above the house that was sold so that no one could block another building or sign. 

Now I'm only getting 3-10 Messages per day.Sometimes people get there and don't like that it's a duplex and they have to share laundry, some don't like that it doesn't have central Air, and some just don't make enough money to qualify or have bad credit.