I say upgrade it. I would much rather enjoy the comforts of A/C and FM radio. I also like the idea of having full pressure oiling and more readily available 12V components. Lets face it, this is your daily driver. Being comfortable every day is far better than having that warm fuzzy feeling of keeping the truck mostly original.

Never hold your farts in. They travel up your spine and into your brain...that is where crappy ideas come from.