Stock 2nd gastank?

[RiCo]

Well ive been wanting to put in a speaker box behind my bench seat in the cab, but i really dont have the few hundred dollars for a kit. So i kinda just dropped the idea for awhile, untill i relized that i have another tank. On the passenger side theres a a place to fill up another tank. So i opened it up and discovered there really was a 2nd stank. My dad and i have never filled this up. But i was talking to him and he said that we would probably need to re-route the fuel lines to this tank. Then take out the one behind the seat.

anyone does this before? what things will i need to do? whats the estimated cost on doing this job?