Now I'm not saying is there anywhere which would say exactly the same, but would every part of both sides suffer an actual direct hit or would the bombs olny hit major metropolitan arias and the damage to rural arias and small towns be limited to radiation exposure?
I'm not sure I understand your question. Are you asking if they COULD do that with their arsenal, or WOULD they bother doing that?
Your question is so broad as to be unanswerable. In addition, it depends on many unknowable factors: What kind of war is it? How quick did it develop? What is the goal of the war? When did the war take place?
... and so on.
Complicating things is the fact that the United States has never declassified its modern nuclear war plans — everything from 1962 onward remains classified. Nevertheless, we do have some information based on the hard work of historians who filed information requests that uncovered background material.
To answer some of the questions I asked above, let's limit ourselves. Let's imagine a war developing out of the Cuban Missile Crisis, with a full-scale exchange on Nov. 1, 1962.
On that date, the United States is operating under SIOP 63, the Single Integrated Operations Plan for Fiscal Year 1963. The National Security Archive at George Washington University has done some really good work uncovering this historical document outlining the creation of SIOP 63.
On page 18 is a partial answer to your question. It contains information related to the creation of the Target Data Inventory, a list of 12,000 sites in the Soviet Bloc that set priorities for targeting. While we don't have a prioritized list of American targets, this is as close as we can get.
Furthermore, we know that the United States had fewer than 2,000 delivery vehicles (bombers and missiles) available to deliver nuclear weapons on Nov. 1, 1962. The Soviet Union had fewer than 40 missiles and 200 bombers with the capacity to reach the United States. (Exact figures for the Soviet Union are still unavailable.)
Though it had 2,000 bombers and missiles, the United States intended to send many of those delivery vehicles after the same target. SIOP 63 predicts some dud warheads and missiles and some bombers destroyed by Soviet air defenses. To ensure a target kill with these factors in play, multiple weapons would have been directed at the same target.
With these factors in mind, we come to the answer to your question. Given this Nov. 1, 1962 scenario, many places in both the United States and Soviet Union would be left unattacked. While American estimates forecast that more than 100 million Soviets would die during a SIOP 63-style exchange, the plan did not estimate that it would destroy every part of the Soviet Union.