The property is in Mount Pleasant.

but those were ground mounted units and current replacement is roof mounted which I think means the heat is handled differently )I don’t really like the idea of an installment sale, it feels a lot like just collecting rent except in the end I lose the property. 

In all my years I find it's tough to find someone (young or old) that gets motivated beyond a certain mount of ready cash even with a lower rent incentive.

@Brenden Mitchum it looks to be a single family home and says in the listing you can use conventional or other https://www.zillow.com/homedetails/8032-Martinsburg-Rd-Mount-Vernon-OH-43050/225329953_zpid/?

Hi Mike, nice to meet another investor from Mount Horeb!

Go find other "wheels" and see what their advantages and short comings are before mounting an effort to build yet another "wheel".   

I'm debating composite decking since it is a LOT less maintenance, but it is expensive (like 2x quality cedar), plus you need a special mounting system.If you can live with the upfront pricing, I'd go for it.

Getting 2 x 4 tons and a crane took almost a week as I didn’t want to spend extra on trane units. if you don’t need large units or they aren’t roof mounted that will pry also save time/money. 

Other downsides for the window units I see are interior water intrusion issues, exterior erosion issues, having to mount brackets and/or install/remove them each year or pay someone to do this, potential lawsuits if installed incorrectly, and issues with the windows they are installed on. 

All walk ups,  we will be using PTACs for HVAC, but I think I can add a UVC+HEPA wall mount filter unit that would effectively scrub the air.