Thought I would show you the finished product.
First, without the propane tanks in place.


and all buttoned up ready to hit the road.


Overall, the hardest part in the final steps was crimping the new battery cables inside. Since I had no white cable, I had to use red to keep black as the positive, but I think I will wrap it in white electrical tape I have some time.
Crimping 4ga. cable is tough, but with the use of a hammer and a brick inside the box, it done now and covered in heat shrink tubing.