Very creative thinking! I have a Dodge 2500 and will check out spots for a box like this and let you know what I find. I already have a crossover box but never can have too much storage space.
That was a good observation about the crash loss and what items would be best suited for it. Tow straps, chains, oil, antifreeze, grease, tie downs, tarp...lots of possibilities. Keep my tools and emergency gear in the crossover.
I like your idea in the instructions of blue taping a bolt to the box wrench. Wow, very clever and I am going to steal that idea for other projects around the shop for hard to reach places.