I have a 2004 Coachmen travel trailer.  The model is Spirit of America.  The back of the camper has what they call a "garage door".  Basically a big storage compartment.  The door opens on a hurricane hinge that is fastened to the inside of the opening and the other half of the hinge to the door.  Over the years the door has gotten wet and is now pretty rotted on the top where the hinge mounts.  I spoke with Coachmen and the door is available but will cost roughly $1000 to get.  I am looking for ideas on how to fix it myself.  My plan is to attach a large sheet of aluminum or steel to the inside of the door and reattach the hinge to it.  Basically reinforcing the existing door.  He only issue I see is the added weight may not be held open with the gas powered struts, which is why I am leaning towards aluminum.  I am also not sure if stronger struts can be purchased.

The other option is to rebuild the door entirely.  Not sure what materials would work best.  The current door is basically laminated partial board.  Marine grade plywood may work better, but the thickness would be hard to match and  weight becomes an issue again.  Any ideas?

you might consider looking into an aluminum honeycomb core material and make a new door.  you can do some research to find information about weight and such.

If the majority of the door is salvageable I would consider a 3" strip of aluminum around the interior perimeter just to reenforce the edges. This would give you a new "point of attachment" for the hinge and would not add much weight.