how did i know this was you....check the pisgah national forest page for the grandfather mountain district. They should have information on wilderness camping permits. Or you can call they have been extremely helpful in the past.
Permits are required on the weekend onlyuntil the end of October. You can get them from the information cabin - a really long way from the Shortoff trailhead - or you could try and call the district office. That has had mixed results in my experience.
You don’t need any permits to camp at the trailhead parking. Everybody bitches about the approach, but it’s only 1.25 miles to the descent gully.
I used to camp on top of Table Rock or at the parking lot near the trailhead. Like Lewis said, either way, the descent gully is incredibly close. There's also some nice camping by the river on the road going up to the parking lot.