Some notes on my default settings:

• the frame, the platform and the hook printed with ABS (200um). Feel free to try other materials.
• the wheels and the axles printed with PLA (200um for axles and 150um for wheels)
• in my case supports were required for wheels only
• print axles in pairs, they are thin and high (40mm) and slowing down the print may be neccessary at some point
• the finished wagon is rigid, but be gentle while assembling (it is not difficult to brake the frame if platform connection slots are too tight)
• sanding may be required while fitting parts together (wheels and axles, platform and frame)
• axles are connected with wheels using super glue

The finished wagon is pretty light: 48g compared to 58g of original one.
The wheels need to be rotated before slicing of course :-)

https://youtu.be/WfGxFVOmLlc