Ive seen people set up like that before, and although we dont stay in "high society" campgrounds, I have never seen a rule that says how your trailer must be oriented.... but I would suppose if you were to set up that way next to a site where the neighbors are not quite as friendly as your buddies are, they may complain due to their being stripped of what little bit of privacy they are allowed by you backing in.. and so its reasonable that there may actually be a rule (that im unaware of) that can be enforced if someone complains.