Reason behind extra tanks?

[CG]

So the K20 I recently purchased from board member Livrat has three tanks. Cab tank and two extra poly type tanks. I never really gave it much thought before, but why did they have the extra tank option?

I guess I could see it if you were hauling a camper somewhere. But I was thinking these trucks were purchased to use as trucks back in the day. I don't think of them being used to make long road trips. Run low on gas in the regular tank ... stop at the gas station and fill it up.

The one thing Ive thought would be an interesting idea is to ditch the in cab tank and run off the two extra tanks instead. Hassle though filling em both up with the fillers one on each side of the bed.