It’s pretty uncommon to replace a whole door, especially since Burro
has been out of business for a couple of decades. It’s possible the door may have been repaired and then painted or re-gel-coated. David’s suggestion might be the simplest: paint the new to match the old.
In addition to the other things mentioned, you will likely need towing mirror extensions. This is a wide-body trailer. You might want to run it across a CAT scale on the way home so you know where you stand, weight-wise. Truck stops, transfer stations, sand & gravel yards, feed lots, and recycling centers are possibilities.
Once you get it home, do some thorough leak testing. Burro
is a “double hull” trailer, so leaks
can run between outer and inner shells and show up at the floor far from the source. Lots of good experience and advice available as you work through any issues that may arise with a vintage trailer.
Best wishes, and happy camping with your family!