Sorry about your situation I can certainly understand. You may be ble to find someone local to do the job for a reasonable cost. Like I said that outside layer can be replaced with marine painted luan wood OR source some aluminum sheeting used on enclosed trailers. Plain white should work. I used to own a KZ New Vision and that was the trailer we did this repair on. Total cost of materials was about $400 but we did not need the outside layer. Cost at the time for a new door was north of $4K.
Good luck hope you get it resolved.