Very good question!!
I search for long time how to enter Rivertown Gorge!! I always transported to Kali's Fortress!! The two ports on the map stays so close to each other ... sorry, I can't find a solution to go to Rivertown Gorge... IF it is a existing area??
And why it is not the same as if I wish to go to Brocken Valley (like a dragon): on that case a mirror asks me: "Do you wish to go to Brocken Valley"... (Yes - No) : that's much more clearer and much less frustrating!
Please, who can explain us this? Exist Rivertown Gorge??