13 years w/ my own moving biz
24 years owning bikes
Keep things square in the box (f-250, s-10, donkey kart, whatever)
Use 2 pair of tie downs 1 as a primary suck the fork tubes down AND square. The other pair as secondary doing the same job as first. Use different mounts with each pair if available ie bars, top tree, lower tree. On bottom... holes in top rail of truck, hooks on side of bed, D rings inside etc.
Don't tarp it, its ****** on paint.
Good luck
Scott