Usually those trucks have a rail that you can get a a rope behind. Along with you tire boot, use ropes to secure it.
I like to put small lengths of rope around these rails. Tie them in a loop. Go fore and aft of the dub, on each side. I am a fan of using the most inexpensive carabiners that ARE rated for climbing, but without the saftey gates [lower cost]. Attach those to the small loops.
From there, tie a rope from the swing arm, to the front loop carabiner [tied to the side rail of the truck]. Bowline knots work well for this. I like the online resource from Animated Knots by Grog [ www.animated.knots ] for this if you do not know how to tie said knot. Also, if you want to put a loop in the middle somewhere, I like the Alpine Butterfly loop knot.
Then tie a line from the handlebar, to the rear loop on the same side. Your lines on this side will be a criss-cross. This helps with fore/aft/side motions.
I would also tie from the forktubes to the front [on their own side] to the forward loops, and same from the swingarm to the rear loops.
To finish it off, I would push-pull and move the bike around. If it seems that it will shift, consider getting some short and stout bungy cords. Use the ropes as the main holding element, but double up part of it with the bungy's. This is where I like the alpine butterfly knot to put a loop in the middle of the long runs. Then hook the bungy to the butterfly loop, and the loop of the bowline -- now you have a shock absorber, and the rope will still hold in the event of extreme movement.
Also, when you make the front tire boot, and perhaps a rear one? [Don't be afraid to screw these down if the floor is wood] Take some rope and tie the rim/tire to the boots or brackets too.
Good luck with the move. If I were closer, I'd be there to help. Strong back / weak mind. Well, not actually. But I love to help people.
Oh, and my love of knots came from my Dad, and I love to teach them to Boy Scouts. Got to love a young man that can lash his own chair out of wood from the forest.