Hit L to bring up the campaign menu, and then join one of the campaigns as a guest (you can afterwards set it as your home campaign). You'll then be teleported there after a short wait.

Edit: Meanwhile is the only way to leave Cyrodiil by wayshrine to wayshrine back to other zones? I was out in the middle of nowhere and had to get back to the wayshrine in the corner of the map to port back to Auridon.