Sorry, there is nothing refined or cultured about Julie's accent. I am as southern as they come and in 52 years I have come across very few people that speak with this dialect or accent. As mentioned above, I knew Julie and her family very well.
This accent was not a "put on" or exaggerated for her... I can barely stand to hear an actor use a southern accent that is not accurate. A cultured southern accent is very pleasing. (think Dixie Carter, Jimmy Carter). Usually someone trying to imitate a southern accent is WAY off.
A fake, poorly executed and faux accent grates on me. Typically they are portraying an uneducated, "redneck" person and even someone that might fit the bill for the aforementioned, rarely sounds as bad as someone trying to imitate the accent.
I remember this Cold Power ad so vividly because people immediately thought all people from Georgia sounded like this....we do not, even back in the early 1970s when this ad was filmed.