There is a quest for the Treaty of Treasure, but that is not the zone you want. You want the one that just says Cove of Decay. There used to be an access quest to get in there, but they may have removed it. If they didn't, that may be why you are not seeing that option. Also, if you are not at least level 38-40, there is no point of going in there. The mobs are extremely tough to solo and there are too many of them to make it worth your while. You have to grey out the zone for it to be beneficial. There is no dodging aggro in there, no matter how good you may think you are. Good luck!