I'm having to completely replace the fuel system in an 87 F150 four wheel drive

At one point both tanks were filled
with water without owner's
knowledge she turned it on and ran it
until it died and it's sat there for
several months. I know I've got to
replace pump any and all filters
sending unit etcetera. I just want to
know if I can run it on just the one
tank without any crazy customizing
to the lines because eventually I do
want to replace and operate with
both tanks. Also is there a website I
can go to that can give me an in-
depth look into the fuel system?