Made some lightweight doors for my Uforce 1000. Wanted to keep weight down, as this is over-snow vehicle that relies on lower weights for performance. Also wanted to not spend a bunch of $$.
Contruction is 1" XPS foam sandwiched in fiberglass with epoxy resin. Then cheap clear vinyl with velcro windows. I designed/3D printed some. basic door latches. Door attached to frame with a couple basic hinges, had to drill some holes in roll cage. Total cost of about $150. Most of the time was spent getting the foam to fit inside the door dimensions perfectly. Was a tedious process for door #1, then trace/repeat for door #2. Doors are probably under 5lbs each.