Originally Posted by ///Matthew
That's correct from my experience. Tourist days are the days when you can just show up and drive. I had the same kinda issue when I was there and scheduled my itinerary around getting to the ring.
Looks like the are open 3/17 and closed again until 3/23.
However if you look on their event calendar there is a track day on 3/18:
Open track day at the ring sounds nuts!