If I remember correctly there is a pass leading to and from High Rock and Skyrim? If so, where is it?

Ha, can't go to High Rock ingame. Closest you can get is Forgotten Vale.

It should be fairly abvious that you can't cross over to High Rock... it takes a lot of effort to make a region.

i think he is referring to a gate that "would" lead to high rock, like that gate east of Riften that would lead to morrowind if there wasn't an invisible wall behind it

There's a road in Haafingar that leads to what would most likely be a pass into High Rock. I think I remember there being one in the Reach too.