won't help with the tank side of things but there is a thread for going with an external pump and filter at:
https://www.classbforum.com/forums/f...ump-10648.html
I partially lowered the Onan, wiggled the cover up enuff to get to the DC line to the OEM fuel pump, then bypassed the weakass pump with an external.
I think I would just cut an access port thru the fiberglass cover to get the DC line next time and not F with trying to raise the cover, then get it back in place.
Your Fuel Pump Frustration May Vary; mine was pretty high ;- )