Cool swap -- but don't make it soo complicated! There should be three small tubes and a big filler. One of the small hoses will be bigger than the others -- that's the pressure supply line from the in-tank fuel pump. The other two smal lines should be about the same size -- one is the return from the fuel pressure regulator and the other is the vent line that runs to the charcoal canister. You can use these interchangeably - tee in one with your existing charcoal canister, and use the other for fuel return to the second tank. Switching fuel supply and fuel return together is the cleanest way to do this, otherwise you might wind up running one tank dry and overflowing the other, courtesy of the return line.

There should be two wires that are significantly fatter than the others -- often, they'll have their own dedicated connector with a yellow weatherproof gasket/bellows. These are the fuel pump wires, and polarity shouldn't be an issue. Connect these two wires to a 12V power supply or battery and if you get a jet of fuel, you're good to go.

I'm fuzzier on the other wires... There may be a separate roll-safety feature, which would account for two more wires, and a fuel level sender, which could be one or two wires, depending if it does fariable resistance to ground or variable resistance to coil. '

If you undo the fasteners for the pump assembly, you should be able to visualize where all these connections go, and IMHO it is a good idea to clean the 'sock' filter on the inlet.

Randii