Is there someone that this community would recommend who could help with establishing a business entity (be it a partnership, LLC or something else I'm not aware of) so that we can buy and sell real estate investments in a smart and careful way?

This guy is too smart and has money.

My question is would it be smart to buy a townhouse or house and that new community and then rent it out?

Smart Move usually provides a recommendation but now it states "Not Enough Information".

Is it a smart idea to sell and then invest into another property to flip or should I refinance and keep the property and buy another one?

If you simply 'must have it', then Mr Masotti's advice sounds excellent (obviously a smart guy with experience).Just my 2 cents.  

Obviously there is more management on my part and more wear and tear, but is this a smart move?

Be smart and protect yourself, screen your tenants thoroughly and provide a quality product and I doubt you will need an attorney anytime soon.

Everything I've read suggests that the technology infrastructure associated with the big guys is the best way to maximize pushing rents and occupancy: dynamic pricing, web penetration, etc.  

If I do decide to go that route, would it be smart to rent for 3 more years in Charleston?