Fuel tank Getting flushed clean and treated

If your not having other problems, I'd drive it. Expect various things to crop up from the inactivity, but hard to say what or when. Auto parts were made different back then (better). I would pull all the wheels and make sure the braking components were worthy and working before driving. Take a look at the rubber goods for any deterioration. Turn the engine over by hand with a squirt of oil into each cylinder to make sure the cylinders are free.