Lambretta scooter model

thingiverse

I'd love to print this model, but unfortunately, the STL file is messed up. I'm not sure where it came from, but I think I downloaded it from the web a long time ago - now I can't find the original SketchUp file anywhere! I really want to print this model. Could someone please help me fix this STL? I've already tried using Meshmixer, Fusion 360, and Netfabb with no luck. Edit: After spending hours tinkering, I managed to make the model printable. I also modified the leg shield to match the real one more closely. However, my Fusion 360 skills are still pretty basic, and Tinkercad is a bit too simple for me...