We have two, maybe three small plastic storage containers. We put the male part of velcro on the bottom to give some bite to the carpet. We added velcro to the sides of container, and side frame of the bed. So the combo of velcro resistance on the carpet, and velcro attachment to the sides, has kept these from shifting while driving.
The items we put in here are light weight. (Rolled up rain gear for really getting out in the elements. Some long winter underwear. Etc. Mostly all clothing that we use sometimes one once every year, or less.)
Now, I keep trying to explain to my DW, that if we could just get rid of the second hundred pair of shoes she carries in the closet, that I could get another full case of vino storage... And, it was a close decision on her part - Shoes vs Vino? Well so far, the shoes are winning out
Best to all,