I had an old carpet remnant that I used on the backside for sound insulation. Just the plywood kills about 85% of the road noise.

Before I did this I installed the bare plywood and when for a sound check drive. Added the same carpet I used to cover the lids on the storage boxes using the same 3M adhesive and staples on the backside. It's just tight enough the bottom is wedged in, there's actually a little grove along the bottom it fits into so no further fasteners are needed and it can be removed in 30 seconds. I also used 1/2 plywood but went all the way to the bottom and slotted for the u-bolts. If you do this don't drill below this bracket or you will have a hole to the outside! Learned the hard way not to use stainless screws as that's some tough steel sheet metal.

This required 3 countersunk sheet metal screws into the seat back bracket to attach the plywood There's no wires or anything behind it and there's no harm to the truck. You are a better carpenter than I am so this cost $47 more for the top trim piece which snapped right in.

For windows instal Super Alloy Ranger