The food box at the left rear is a unit I built over 20 years ago and has seen a ton of use. It houses all of my cookware plus a good amount of food. An overhead rack at the front of the canopy-hard to see here-holds all of my wading clothes and nighttime warmies. Lights front and rear are controlled by switches at the rear and on the units themselves. An old flourescent lantern provides more light and some new LED lights front and rear supplant the older lights. A spotlight on an extendable cord resides in a rack on the left rear.
The tall canopy is a vast improvement over the cab high model I had on a previous truck. Cab highs are like spiked heel shoes the ladies wear-stylish maybe but an absolute pain in the ass to deal with. Screened windows on both sides provide ventilation and I have built a mosquito net frame for the sliding front window that keeps me insect free at night.
In the last picture the truck is ready to go, I just need to add ice and a plastic milk crate with some of the softer food items. As shown it has all the cooking gear, stove, water, 3 sleeping bags, 2 pair of waders and boots, 5 fly rods and 5 reels and 7 lines, flies, vest, wading staff, enough clothes for 5 days, 2 raincoats, camera, monocular, a chair, fold-up table, a pisaroonie for nightime use, propane and all the other paraphenalia and detritus that finds it way along on fishing trips. It doesn't appear or feel crowded at all. The old Ram single cab truck came with a lot of room behind the seats that includes a full width tray, snap in trays up the back of the cab and a storage net. A mountain of stuff can be stored back there out of sight and out of the way but easily accessable.
If you have a skil saw and a sabre saw you can knock someting similar out pretty easily. A table saw and a router will make it even easier. It was a fun project but more importantly it has served me well for several years while holding clutter and chaos to a minimum.