Okay , an Idea !
Some folks on here have been shipping sail ships and parts all over the place ! Here's an idea for you . I assume you don't want broken stuff recieved by the final stop , Right ?
Now here's one way I have used for years . Take All the parts for , say the Mainmast ( Except platforms ) and tape them together rolled up in the thin foam you get with electronics or at the U.P.S. store .
Now that you've done that Get a small mailing tube the right length from many of the shipping suppliers .Wrap a final thickness of foam around the whole thing . Get a small Flat Shipper from the U.S.P.S. ( Small Envelope , Put two layers of cardboard together with the platforms fixed to one side ). Tape works fine . Put the two pieces together parts trapped between . Slide in the envelope and close , address and ship along with the tube .
You'll find everything arriving safely and none the worse for wear . This works for wood mast and platform parts too ! I ship things like 1/96 scale 5"-38 units in Ring Boxes this way too . T.B. P.S. I use the Tubes that plastic clamps come in , ( the clear ones from Harbor Freight ) to ship small boats and P.E. Stokes stretchers in , and Floater Net baskets too !
Cardboard tubes work too , But you have to just about force all the wrapping in it to prevent it from being crushed .