I imagine the devastation to cities and civilians would have been devastating, but my understanding is that a significant portion of the population, especially outside Europe and America, wouldn't actually perish in the blasts, as would a large amount of military troops (I imagine). But there is the challenge of the nuclear winter and remaining enemy forces.
Was the plan to just try and rebuild/survive? Were there plans for forces in Europe to make moves? Naval forces?
Were there plans to survive the winter? Wait it out in bunkers?
I've seen a lot of text regarding what happens leading up to and during the war, but very little discussion of what comes after.
I can't answer much, but I just finished reading One Nation Underground by Kenneth D. Rose. For the Kennedy administration, the military doctrine dealt with flexible response. Kennedy could be flexible with responding to attacks with conventional warfare, diplomacy, or nuclear retaliation. Following a nuclear attack "the United States would still have sufficient military assets (a “second strike” nuclear capability) to 'inflict an unacceptable degree of damage upon any aggressor.'"
Rose also stated that the administration pushed for the construction of fallout shelters, but it never gained traction due to a mixture of ethical, economic, and social factors. One of the issues of fallout shelters derived from not knowing enough about fallout. The Eisenhower administration looked to evacuate targets, but nuclear fallout travels thousands of miles. Some scientists estimated that "ditches would be covered by tar paper, and would provide shelter for fleeing Americans caught out" during an attack. Even during the Kennedy administration, citizens didn't know how long they would have to stay underground. Some scientists estimated staying within the shelter for only 48 hours would be long enough.
And that's all I really know. I hope I was able to help you out a little.