The first mods to the 1969 Avion family camper (done around 1970) was to remove the battery from inside the camper (acid smell had to go) and pipe a copper filler pipe into the water tank so the tank was easier to fill. I repiped that fill when I restored the camper. Now, to fill the tank you just hook the hose up to the copper pipe and open the gravity filler. When the tank is full, water comes out of the gravity fill and lets you know that it is full. It is much easier than using the gravity fill, which is still available.
