There is no current requirement for access, although the former access quest, Vale of the Shattering, can still be undertaken.
An additional way to access a similar zone in the same place is by doing the quest The Invasion of the Vale which begins with a letter found on the body of a dead messenger in Antonica. If you have the quest to kill the bear at the same time as the Invasion quest, then after the last named (of the series of 3) dies, the bear will appear in the zone as well. There is no need to leave and re-enter. Do not leave before you find the bear though, because there is a lockout timer, and it's 4 hours for success (for the Invasion zone).
On a TLE server, the command to look at lockout times is Alt-Z for Zone.
There are a few low-level gnolls on the trail leading into the zone, and then packs of L16-17 gnolls running around it. The gnoll packs are on a 5 minutes real time respawn timer - you can ignore them but they'll likely run into you and complicate your fights if you don't.