My only issue with mounting in the bed or my truck is I have a 2nd gas tank already in place.
I have a Transfer Flow 40 gallon auxiliary tank and the only place to mount it would be to make a frame to go above that.
I will have to look into if my trailer is prepped for a gen, I know it was prepped for a second battery but did not notic anything else while I was in there.
And I wasn't sure if having that dolly wheel would throw me into that category or not.
As for the design of the box itself I was thinking of building it out of aluminum with fiberglass sides and sound deadening material on the inside. He material is also fire rated so it serves double purpose and is light weight.