Carpets are rolled face in from the mill, so a solid white colored plastic, brown FedEx colored wrapping paper or clear plastic with cream latex backing showing would be spot on.
Having unloaded many a carpet trailer over my flooring career I would pass on a side door load/unload. Only an end door boxcar would really work. Those rolls in scale size would run 800 to 1200 pounds. Lots of problems either loading or unloading with a fork truck bong. Super idea for an open tractor trailer door at a dock. Drill a hole in the rod to fasten it to a fork truck. Neat wrapping idea!!
Speaking of Empire... we had them install 3 floors of stairway carpeting in our home, and were VERY happy with the quick response, reasonable price, and very good work.
Really looks good! Never seen something like this modeled before...