From the page: "In the past TES games, people have attempted to mod multiple parts of Tamriel into the existing game. But making such huge detailed land masses that are true to the lore is difficult. So it窶s possible that Bethesda added those since they rely a lot on the modding community. It may seem like wishful thinking, but I can窶t think of any explanation for it! Can any of you? You can check out the other provinces on your own in Skyrim if you follow the directions stated, and use the no-clip console command. There is also a youtube video showing someone no-clipping to a few of the provinces. "