Is there any overflow parking if you have more than 2 cars at your site?
I did not observe any overflow parking. The entrance to the campground is small and you must immediately turn right to start down the narrow, one-lane road that wraps around the grounds. The host site is immediately on the right at the front. There may have been some limited additional parking spaces on the left of the entrance but you would have to drive around the entire loop til the end to park there. Again, I did not observe any additional parking spaces so I can't say with confidence there is any. The campground is also right on the main thorough fare that runs through the park so there is no parking there either unless you are temporarily pulling over. If may be able to park at the hotel/gas station/giftshop up the road a ways but that would be quite a walk back to the campground.
Get an answer from Stony Creek Campground staff and past guests.