[NextNewell]

You need to break this down to individual sections and check them out. At this point I would disconnect the wires from the W/D at the breaker box. Gordon can chime in here but I believe there is a breaker on the generator that would assure it is totally disconnected from system. I would turn that off as well. Then install new fuse in TXfer box and test again.
Wear your shock resistant rubber soled shoes while working on it.
Do you have an electric water heater in this coach?

Checking it by sections is what I planned to do. There is a breaker on the generator and the water heater is electric as well. 

So if the neutral was hot for a split second, could it have essentially electrified the entire coach looking for the easiest ground which happened to be the SS hose behind the W/D, which could explain why that was burnt. And then using that line of thinking, could it have fried something else that was plugged into an outlet which created a short that is now causing the fuse to keep blowing? And could that explain why turning all the breakers off doesn't help?