As described by the text of the sim: "At the northern boundary of Winterfell, the veil between the worlds is thin. Here the lands of humankind meet the realm of the Fae. Anything may happen, and often does ... Winterfell Borderlands is an Adult sim, but otherwise public."
I spoke to a couple of people here, and they helped me discover some parts of the sim that might have escaped me, otherwise. Much of it is hidden (and I don't refer to the skyboxes when I say this)...
The sim is rated adult