If the door frame is not welded metal, can it be disassembled and the inside panel replaced with your choice of some other material? Some of these doors are 'sandwiches' of filler and outside paneling, but the paneling itself may be glued to the filler and can't be peeled off.
Or you could try Colaw RV Salvave in Carthage, MO, for a possible identical replacement.
Haven't heard of this happening before...
2016 Tiffin 40 QBH
2015 38RSSA, traded
2005 TK3 #1869, 10 yrs of memories,
2017 F450 KR--one more Ford is it
2009 F450 4x4-died; 2010 F450-retired