The instance consists out of two wings. Although you can't skip the entire instance, you can skip the boss in the first room and the boss in the left wing. When you reach the river/water in the instance, turn towards the right. You'll still have to fight your way through the right wing of the instance, but its possible to walk around a lot of groups (I think you can even walk past the 3rd boss) if you hug the walls.

Oh, and there's a hole in the path right leading towards the last boss, careful not to fall in or you'll end up at the start of the right instance wing again.