In addition to all of the above, make sure to secure them in the back, no matter how far you travel. It doesn't matter whether or not it looks like the cab will be able to move or not.
Just ask someone who lost the back window of their truck when the Centipede they didn't tie down slid forward when braking suddenly.
Also, make sure the marquee, bezels, and control panels aren't loose. Quite a few people put a complete game on the truck, then find they lost something when they get home.
Oh, and don't leave any loose parts in your truck unattended, even for 5 minutes. Right, Karl?