Can Reed figure out a way using his intellect to stop a rampaging man of steel,with all the Marvel Heavy weighs off world on various mission ie Sentry,Thor,SS,can Reed figure out a way of stopping him,using all his advanced science.
What do you mean by prep time? Time enough to research the physiology of Kryptonians, come up with some means of depowering him and a method of employing it that Superman couldn't avoid. In theory, yes. But then Lex has been trying the same thing with better resources, not to mention having Superman in the same universe to study, he never succeeded. So there's no reason to assume Reed would fair any better.