It sound like the water line is not extremely long, especially being in a Truck Camper. So... any possibility of just running a semi-stiff bare wire through the pipe and let the wire break free the accumulated gunk? Kind of like running a cleaning rod down the barrel of a shot gut. In other words, snake it out? Perhaps the wire would break some of the gunk up, it might be enough to free up the remaining slime and it can be flushed out then. Maybe someone will come up with a better solution. This is just my initial thought and probably something I'd try first, before ripping the plumbing out and dismantling RV appliances.
Edit:
Another idea just hit me.
You know, automatic dish washing liquid cleans dishes, lime, water spots, grease and a bunch of gunk from dishes, right? Maybe a strong automatic dish washing liquid solution poured through the pipes and then a good flushing afterwards might clean it up too. Here again, it's worth an attempt before dismantling the camper.