1987 ford f150 lariat with dual fuel tanks fix it or junk it?

My husband has a1987 ford f150 lariat with dual gas tanks, something is wrong with the fuel system gas comes from rear tank into front tanks then overflows, this can't be a good thing. My husband is insistent there us no pump in either tank but has a fuel reservoir instead, is that correct? The ac doesn't work and breaks will sometime sink to the floor when I have drove it, he says its way I drive. I'm sure there are other things wrong as well. He said he has a friend who had a 1988 and problem was the radiator, my dad knows quite a bit about cars and is convinced my husband is mechanically challenged and it would cost more to fix everything then to just sale to salvage yard, or junk it because my dad said car isn't worth a thing. We bought this truck in 2012 with over a 150k miles on it. It has done more sitting in drive way than driving. Would it be cheaper to junk like my dad is suggesting, will it cost more then value of truck to fix. Can anyone give me an estimate of what the truck might be worth?

Sounds like it's worth about 25 cents per pound for scrap metal.