PCV for adding a fuel pump to Champion Inverter 3100

i need to watch that video again
but depending on where it is placed, it would allow intake vacuum to operate the pump without the reciprocal back pressure to damage the pump

Biggest thing I found out is that the cap on the Atwood tank needs to be cracked or it built up pressure in it.

sealed tank, with fuel being pumped out, would built a vacuum inside the tank
sooner or later it would stop
air must be allowed in, to take the space of the fuel being pumped out