Having been raised in Kentucky (Winchester and further north), there were only two phrases that puzzled us when we moved to Columbia:

• "From off" - the meaning became evident quickly, and people were kind to explain things.
• "Don't care to" - took a while. It means "I'd like that." (the opposite of what it might mean elsewhere)

One other common "phrase" was also difficult.

• "Where is Dr. Max Downey's office?" - "Where the old post office was."
• "Where is Dr. Janella Brown's office?" - "Near where the candy factory was."
• "Where are the new fairgrounds going to be?" - "Out near where Oshkosh was."

We have found it common in the south to get directions based on where something used to be.