Joy A. here....
I couldn't find a pre-made tongue box that was tall enough for a standard 20lb/5 gallon propane
tank, also the tongue on a 13 footer is shorter than the 16/17 footers. I contemplated going with a smaller shorter tank but then I thought about dry camping
in the cold climates. I'd be using the propane
for not just the stove and fridge
but also the furnace
My generator/propane box is roughly 39 inches wide in the back and 31 inches wide in the front by 15 inches deep. It's roughly 21 inches high to accomodate a standard 20lb/5 gallon propane
tank. The box on the side is removable and is an exhaust diverter. Oh, and I lined the generator
box and divertor with that window bubble wrap sun shade. Used 3M spray on glue to adhere it.
I can't seem to locate the sales tag for the diamond plate I used and the tray that the welder fabricated for me. But as I recall it was in excess of $300 closer to $400. Aluminum diamond plate is very pricey.