The Walmart in Dahlonega doesn't mind and neither does the older shopping center. Both have groceries and supplies you can't get in the historic downtown. Both have plenty of parking. Both know you're likely to shop their stores on the way back to your rig. Parking your RV there is fine with them as long as you don't spend the night there.
It's common sense actually. Driving your RV in the historic downtown narrow, one-way streets is a hazard even if you're a pro at driving. Taking up more than one parking spot in a historic district isn't courteous. The advice of our friends: If you wreck or cause damage you'll be ticketed. If you're parked wrong you'll be ticketed. Go park in the old shopping center or Walmart.
Squeezing through narrow one way streets isn't smart with RVs. They've had too many RVers causing problems there.
Just. Don't. Do it.