I wanted underground at a property and they would have gone the whole distance in the air but I had to pay a portion because the cable was buried.

Just a safe livable place, it all depends on what you are doing and if it has to be brought up to code based on what you are doing, ex: new kitchen will need all outlets brought up to code and depending on the size exhaust hood for the stove that may need makeup air brought in if the fan is over 400 cfm.

Air BNB or MF/commercial is your best best. 

Should I Invest in nearby city and do air b n or stick closer to Charleston or even in Charleston? 

There may be cool air seeping in from the outside reaching one side of the wall and the warm interior air on the interior side of the wall resulting in condensate. 

How long as it been on air bnb?

If you have a larger system with a hot water circulation system, it may be air trapped in the lines.

End state is have top floor rented,  bottom renovated and  plan on using 1 to 2 of extra bedrooms (it is 4/2 downstairs  as  an Air BNB,  and a possible third revenue stream by renting out detached garage .  

If you have the ability, maybe consider renting out a room in your home on Air b&b or as a monthly rental - also gives you the flexibility to get rid of people easier.I recently read a blog post here on BP by a guy who had set up a curtain and was sleeping in the living room while renting out his original bedroom.

When a property built in 1988 has the original air condition condenser, it is a safe assumption that the cap ex will be cashed in sooner rather than later.