To get movable tracks, print them with flexible PLA. If you use standard PLA for the tracks, putting them in 60°C warm water helps mounting them (depends on the used filament).For printing the tracks, brim should help to hold the printed parts on the build platform.As the axis for the track reels and the holes of the reels are concentric, a little bit of oil might help to mount the reels on the axis.The fitting of the parts (especially the track reels on the axis) depends very much on the used filament and also the used print temperature. It might be necessary to adjust the size of the reels slightly with the slicer software after a first test print.Support is necessary for the chassis and the first arm.All in all printing the necessary parts isn't a big issue.Have fun!!!!   :-)