If you visit a Guild Hall, you can always return to your previous town or outpost by using the "Leave Guild Hall" button in the Guild window (G). For this to work, you must be in your own Guild Hall, and not another one in your Alliance. You can always switch Guild Halls as many times as you like before returning to your own, and then use the Leave button to return to your most recent PvE campaign location. This also works for group map travel, and will use the most recent location of the party leader. This is especially useful for returning to locations in the Domain Of Anguish, which normally takes 2-3 map travels otherwise.