Removing the door is a matter of drilling out the numerous rivets on the outside of the door frame and removing the screws at the bottom. The interior has an aluminum trim that surrounds the door on the inside. The door itself comes out when the rivets are drilled out (and screws removed). The interior aluminum trim covers the gap between the door and the interior panels and any fastening that is on the interior trim in that area. I would try gently prying the aluminum trim to see if it isn't a friction fit holding it there. You might call Inland RV to double check that this is the way to remove the door and to get the aluminum trim off on the inside.
1966 Airstream Caravel
2006 Toyota Tacoma