I'm looking to do a vapor barrier to reduce any potential moisture, Insects, raydon, just better over all air quality is what I'm going for.

Alternatively, get someone to manage it as and Air BnB.   

What happens when you get a tenant that likes fresh air and leaves the windows open, but also likes the place warm and cranks the heat to 80*? 

The air base is expanding significantly. 

@Jordan Smith sounds good, thank you!

You should start by getting estimates from contractors to determine approximate roofing, heating/air, and what other repair costs are going to be, once you have those numbers, that'll make it much easier to make a determination if the after repair value justifies the expenditures....

Im in about the same steps of the process as you, but I will say- Air DNA is very much worth the value.

Needs a new roof the AC units may have to be replaced, the building is infested with mice and rats so we might have to fix the air ducts the repairs that were done have to be redone.

Example: An air conditioner goes on the blink and it takes the property management company 3 to 5 days to get price quotes and then has to make several communications with the property owner to get an approval.

Our longest tenant has been 3.5 years, Air Force.