I used a clear vinyl table cloth and cut it, to the same configuration as the door. I then used Velcro to secure it to the outside frame of the door. The nice advantage of the vinyl is , I can fold it up and store it in a drawer or closet. I would have posted a pic, but the rv is in, indoor storage for the winter.
( I hate keeping the door closed in the summer and fall )
TV= 2012 F-150 FX4 Supercab
FW= 2011 270ret Crusader
Hitch= Reese Pro Series 16K Hitch