I'm restoring a Westphalia trailer, slowly, since I don't have a trailer hitch.
But if I was going to make a teardrop, I'd start with a 4x10ft piece of
swingdoor material, and Box out over the wheels like a gypsy/sheepherder's wagon.
And if the shell was
Polymetal, it would be [a little]/[no] more expensive than plywood, but would weigh 1/5th as much. Plus being more durable.
Shaped like this, of course.
