Need Suggestions for Packing a Completed Structure

One way is to place the model in a plastic bag, from what you describe it may fit in the ubiquitous size which grocery stores use.  Inside that bag place cushioning material, most people would choose expanded plastic peanuts.  You will then have a unit with the model inside protected by a cushioning material(s).  Place that bag inside an appropriate box and place cushioning material in the box.  This method is used by FedEx for their shipments and your home to home move should not subject your package to that much jolting and jostling.   John in Lansing, ILL

Thanks John, I appreciate your suggestions and comments.,

You mentioned it is shoebox sized. Get a metal ammo can at an army surplus or gun shop, or even a plastic ammo can . (I think Menards sells the plastic ones).

Use SOFT foam like seat cushion foam (you can get it at Walmart in 1" and 2" thick sheets but it is sometimes cheeper to buy the $3 bed pillows).  Shred the foam, line the box or can bottom. place your model in the foam then surround it with more shredded foam till the box or can is full.

It's also easier with shredded foam to remove your model.

Shredded foam will cushion not crush like peanut packing will.

Best of luck

I always use a box in a box for fragile items.  Peanuts may be too course for a delicate structure in the inner box.  Consider using puffs of cotton in the inner box.   I would use peanuts between the boxes.  Gotta leave a crush zone around the item in case Murphy trips over it.  Have never had a shipping loss in two decades.

I just shipped a Woodland Scenics THE DEPOT(no factory box or base) to a fellow Forum member.  If you are not familiar with this model its smoke stake has two guy wires, its semaphore is in the horizontal position and it has various detail parts including two free standing hand rails.  My wife suggested a larger than normal plastic bag from a retail store.  I put a few plastic peanuts in the bottom of the bag(setting on a flat surface) and placed The Depot on those.  I then added enough plastic peanuts to cover the model and fill the space to the inside of the bag.  I twisted the empty part of the bag and secured it with tape.  I used a heavier than normal cardboard box which was designed to carry six 1 gallon jugs of water.  I placed bubble wrap on the bottom, placed the bag with The Depot in the box and placed plastic peanuts in the empty space.  Another layer of bubble wrap on top of the peanuts before I secured the lid of the box.   It arrived via USPS in fine condition.  John in Lansing, ILL

A year or so ago, I came into possession of a group of fine scale HO cars that I sold on eBay. I would wrap them in cereal box cardboard cut to size. I would stuff the ends lightly with Kleenex. If I had them available, I would then put them in a HO kit box, also stuffed with Kleenex, then place this box in a larger one. We also ship clocks. Packing fragile items is an art form in itself and if you pack the items so they don't move in a smaller box and then a larger box with peanuts, they should arrive safely. DON'T put fragile and cautionary warnings on the package. (Guess which package is used as a football?) 

Our modular group moves a lot of stuff.   Fabrication of wood boxes seems to work.  

Bridge for turntable.

Some is a work in progress.  Turntable/Roundhouse modules in my truck. 

I want to thank everyone for their great responses, they are very much appreciated.