Entertain on the low maintenance fenced yard.

Not necessarily a yard, but porch or balcony.Being in SC, air conditioning is going to be key.

If the property has three bedroom and two full bath then just go ahead and do a nice neutral paint job, get $10 sq. yard carpet (apartment grade installed price), make sure all appliances and HVAC + water heater is working well and list it for rent.

The second was a great deal, we bought it well below value and our construction company rents it from our properties company as a shop and yard. 

Since there is no place to put a drainfield in for a new septic system because of the way the yard is configured, the cost for the type of system I would need is around $30,000 I have been told.My question is, if my numbers still look good after getting a firm quote from the contractor, having a home inspection done, and the cesspit clears the inspection, would you recommend proceeding with the purchase?

Property also has a pretty big back yard.

You can sit and wait for a cash buyer, but the longer your house sits there with a sign in the yard the more potential money your losing. 

He even roped off the property lines (4 feet into my yard) and put up no trespassing signs and private property signs everywhere.

We had a virtually identical tower in the back yard of the rancher my parents built when I was a kid. 

This house was located at the bottom of a hill and all the rain water from the homes up the hill would flow down to the back yard of the property.