OK, now I am getting confused. The link you provided describes access roads from both the north (Rte 550 to Rte 7900) and the south (Rte 9 to Highway 57).
But beware - from the north, there is apparently signage indicating that access can be had via Rte 57. However, this source
https://www.nps.gov/chcu/planyourvis...traveltips.htm
seems to say that the north approach on Highway 57 is permanently closed, and the proper access from the north is now Rte 550 to 7900 to 7950.
It would seem wise to phone before going, especially if you plan to approach from the north.
Bill