There are at least three separate campgrounds on the main loop. At least two more more campgrounds in the eastern part of the park. Go to their web page where they have extensive information on all of that.
I did not see any camping; however, much of the road was closed (July 2017) that would have made the bigger loop.
You can park in your car and stay overnight in the Kohm Yah-Mah-Nee visitor center parking lot only. It's $16 a night. There is also extensive information on regular camping as well on their website.
If you are asking if you can stay in car and park overnight, the answer is No. Rangers periodically patrol the parking lots.
Thanks! Your answer is awaiting moderation.