Just this year I hauled 40 built planes to Brodaks, of various sizes. And I've boxed a number of shops. So I have some comments.
The hardest part is the built models. Not sure how many you are talking about and how far they are going. However, the technique that has worked for me is to set the models on the floor of a cargo trailer, similar to my 5x10 cargo trailer, with the tails outward. Then lay a layer of moving blankets on top. Repeat layers of planes/blankets.
As others point out, I would not allow any person who is not experienced at building and flying models handle any built model.
Regarding balsa, if your building style is to scavenge, I'd keep 100% of it, including crashed/odd+ends.
Props box easily. Engines, as well, possibly wrapped in rags, paper, bubble or similar. And, of course, well oiled.
Kits travel pretty well, too. To retain value, avoid any tape/writing/labels on the boxes, especially on printed artwork. Instead, cut a piece of brown paper 3" wide, wrap it around, and put tape on the brown paper.
Another thing to avoid is using rubber bands for any storage purpose, as they become a mess of glue in fairly short order, especially if exposed to heat.
Best of luck with your move. Hope to see you at a future contest. You are not too far from plenty of CL activity.
Peter