hey guys, i would appreciate anyones help on this. i want to build walls on my pick up truck for leaf and debris collection. so i can haul more things more securely. i have a toyota tundra with 6.5' bed. i will use 4 2X4s in the stake holes @ 4' each. i will use 1/2" plywood walls @ 4' high. (is this too high)? the things im concerned about are 1) the box is attached to the truck only by 1 lag bolt in each 2X4. doesnt seem secure enough. is it? 2) the 2X4s going in the stake holes being modified to a smaller size to fit the opening. will they break? is there metal - square steel tubing? do i put the plywood on the inside or outside of the 2X4? i think outside would be better thank you!