No expert here, but if any of the models are correct, even if it does turn north later than earlier it'll pass through north GA and the Carolinas Monday and Tuesday. That should leave enough time to dry out, and dissipate any flooding that might occur on the river at the park. I'm planning on being there unless it's still raining on Friday.
And to answer your question about camping. Yes, there are still plenty of spots open. Check out the "check in" thread. It has sites listed, number of people signed up for those sites and maximum occupancy for each spot.
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