We have a keystone passport 219bhwe that has lost the cap for a round hole in the front frame that gives access to the storage for the sewer hose. No idea what to call that to look for a replacement. Anyone know?
You may have to remove that "specific brand/specific sized" outer flange and replace the entire assembly. Trying to find a "door to fit a specific flange" without knowing the brand will probably result in you having a front passthrough compartment filled with "don't fit right" doors.... Every manufacturer makes theirs with a "new and improved locking tab" or a "better than the competition detend on the flange" or ?????
It'll probably be much cheaper and significantly faster to just count the screws, measure the flange diameter and order a new "complete assembly"... Chances are very good that nobody sells "just the inside part" anyway...