Here is where I had some thoughts, (still not executed)
https://forum.v1e.com/t/the-perfect-crate/45084
in particular
The rough dimensions I was looking for are about 12 x 12 x 48, which unwraps to 48 x 48. If it were shorter at 30" then it would be rather tiny for a LR. Oversize baggage might be worth it.
Also I think it’s worth thinking about how the weight is supported within the box. Everything can be padded but if some are more rigid than others, then a shock load will stress the attachment points. If the trucks are wrapped in bubble wrap and the center is stuffed with soft urethane foam, it might be relatively rigid support at the ends and compliant in the middle, and when someone drops it, the weight (intertia) of the gantry applies to the lead screw. But if the strut were supported near each end with a semi-rigid brace (I’m thinking a 3D printed custom brace for shipping) and the ends were suspended away from the sides and packed with compliant foam, then the same shock is the weight (inertia) of the trucks, not the gantry.
The strut support should still have quite a bit of compliance/padding to reduce the g forces, but the point is that the trucks should have more compliance so the stress is from the mass of the trucks and not the mass of the gantry.