Roehl phase 2. What to bring?

I'd take an extra large sleeping bag and pillow. Use sheets after you are assigned your own truck. You're supposed to sleep in the bottom bunk when the truck is moving and your trainer will have his sheets, etc. already on that bunk. It's easy to unroll your sleeping bag and use it, then roll it back up when it's your turn to drive.

You can't get proper rest on the top bunk when the truck is moving because all sway, bumps, breaking, etc. are amplified on the top bunk because you're much higher than the center of gravity. You'll be exhausted; like a cat hanging on to an elephant as the elephant rampages across the Serengeti:

 

talk to trainer before you bring anything more than atlas, clothes, toiletries & shower shoes, phone & charger. You're not moving in. You are borrowing your trainer's space. Don't take more than necessary.