Storage of equipment in work vehicles has been an almost constant irritation of mine since I started working for myself 13 years ago.
Over the years I've worked out of old beater trucks (large and small), an SUV, a cargo trailer, new trucks (large and small), an old van, and even commuted out to one job in the country on my scooter one summer.
I've noticed that with my (and many colleagues) extended cab work trucks, the back seat area is usually full of equipment. Some tools and materials need to be protected from the rain, snow or thieves. It almost always ends up a mess, unstable and impractical, because the floor is uneven. Well one day a couple of months back I had enough and pulled into the hardware store and built myself a simple set up that has worked much better...
Made from 1/2 plywood with a rubber runner glued to the top to make it less slippery. I painted the 2x4" feet black. There is a small board approx 1.5" thick used as a spacer under the plywood in the middle front - this keeps it level and supported in the centre, as the carpet profile there slopes down.
This solid, level foundation helps keep everything in place and stackable. It makes retrieving items much quicker. I can now carry more equipment back there. Storing things in milk crates is convenient for loading and unloading. The flat surface makes carrying paint pails inside the cab when it is cold much easier. Long skinny items like extension poles, booster cables, rolls of poly can be tucked in to fill holes underneath.
Most importantly, it gives me peace of mind knowing my stuff is organized and secure behind me as I drive. Can't believe it took over 4 years of irritation for me to finally solve this issue for an investment of $50 and 90 minutes. A side bonus is that when my daughter sits in the back on her booster seat, her feet can now rest on the shelf, which is way more comfortable for her. It easily lifts out anytime I need to remove it and there is no damage to the truck, in fact, this shelf helps keep the floor looking like new.