True. Just making sure you got your bases covered
Ok. I had thought that, despite Darkfall Passage being the only in-game way, there's no reason an intrepid traveller might not, by chance, find his way in from the outside.
Even in the Vale, in-game, there is a cave high up on a glacier where a load of glacial melt water flows down as a waterfall. You can reach it by using the Paragons, I think, but the water does flow out from the glacier itself.
I thought that, by falling into a glacier and stumbling around there for an indeterminable length of time, he could find his way there by following the melt water flow. There are at least a few glaciers running into the Vale, and if Sander fell in somewhere high in the mountains he could follow it and eventually find his way into the Vale.
As I said before, he doesn't know what the place was, or that it was a snow elf refuge containing the Chantry of Auri-El, and he's not going to go around fighting dragons and finding Auri-Els bow or anything ridiculous. That's not how I roleplay.
It's just a short story about how he finds himself in this strange place and interacts with the animals there.