#2 on the popup Gizmos. And if a person camps alone, I highly recommend the velcro strips for ease of attachment to the trailer...
As for the guide wire, I would guess it is different between trailers. Mine has a bit fo slack in it and the door fits tight, but it fits. A friend of mine has one and his guide wire has even more slack than mine and the door fits ok.
I guess I would ask if the trailer is leveled, side-to-side and front-to-back.