James Martin was one of my professors and is board certified in real estate:  https://jamesmartinpa.com/I have to admit that is surprising as I live in Apollo Beach and there are Air BnBs surrounding me and I know very little comparatively is zoned lodging. 

For many people in NYC, the Air BnB model offers a significant opportunity within the framework of your primary residence - for example, if you live in a 1 bedroom apartment right now, possibly get a 2 bedroom and configure it for guests to stay while insuring your privacy.

The property has a great 20 year track record using air b&b and other sites and my aunt is selling it to me.

But my heart wants me to invest in Big Bear Lake so I can take advantage of the thriving Air Bnb market there, as well as have a ski trip getaway every now and then.

Del Rio is a small town on the Mexico border whose primary source of economy is the nearby Air Force base.

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.