I guess better late than never, I've been out of touch for a while! I have the box for my '04 and you cannot open the back door with it in place. Not sure if this is true for the other accessories?There is (or was) a swing-away accessory which mounted on the ports, incorporated a hinged frame, and carried normal DPS accessories on it. This would be in addition to the receiver, the tray, and the box (and would mount between the receiver and tray). Is this the hinge noted in the drawing markup, jake696?
I assume that without this, the box (but not tray) would need to be removed to open the hatch.