In case no one has pm'd you, going around the perimeter of the zone should work, I'm not sure why it didn't...think about as you approach the Bronze Doors Fortress...you see the path up to the fortress ahead of you, and there is a lake to your left...instead of going up to the fortress itself, look out over the lake on your left...you should see a ledge there, carved into the cliff, with a short path leading up to the ledge...just pass through the lake, there will be riverlings lounging around, and you should see the path. There are guards there, in a small lookout hut, you must keep climbing up, and enter into the old mining tunnel. It's lovely and quiet up there. Enter the tunnel and you will see nice creatures to fight or admire, the Velnishi, and at some point a narrow path to the left, which leads you to the lake you are looking for. And there are a couple of tiny lake mushrooms on the banks of the lake.
Good luck to you, and I totally agree that it is hard finding information...sometimes, especially when it is later at night (GMT -7 1 a.m. whatever that is for you) you can enter the gossip channel and find very sweet helpful people there. Ask your question, and while some people may bark at you about "don't ask here!! spoilers not allowed!!" you can safely ignore them, since asking questions is totally legal, and people come out of the woodwork to /tell you the information you need. It's really helpful when you are frustrated, and super kind too. I'm sure many newbs have stayed from helpful players, and many have left from rude players. But there are more sweet ones than rude ones.
Anyway good luck really, I'm not playing atm from rl business or I would offer to take you right to the spot.