This might give you a "visual" as to how much room WG equipment takes up in the truck. Our box is 22' long, and we have store everything in the front 2', leaving 20' available freight. We have never hauled a load (yet) that required us to use the entire 20' of space. If needed, we could easily re-arrange the cart and pallet jack to free up the space.
We store our furniture pads (24) on one of our 2 furniture dollies (Thanks to Phil Madsen for that great idea!) We use a couple of bungee cords across the top to keep them in place.
The two black storage containers hold our straps and corner protectors, as well as some bubble wrap and shrink wrap. Picked them up at Lowe's. The smaller black box contains rubber bands for the pads and some smaller straps and bungee cords.
The red tripod dolly came with the truck. We purchased the aluminum one ourselves. It weighs less, and also can be used as a tripod dolly, and it lets down and can be used as a cart. (Also from Lowe's) We secure them using several heavy-duty bungee cords. The pallet jack came with the truck. I modified a strap, replacing the normal 3' fixed length end with a shorter 6" one. This saves space when strapping the pallet jack to the side of the box.
Hard to tell from the photo, but we carry 10 load bars, and also 24 e-track straps in various lengths. Also we have 4 - 4' x 4' sheets of 3/4" plywood in the front. This can be used as decking or to roll carts over gravel or to protect floors. The ladder is not required, but you never know when you are going to have to have it to replace a light on the box. We also carry two brooms to sweep out the box, a regular as well as a push broom.