3. China's nuclear doctrine is entirely defensive, and it really relies more on tactical strikes along the Russian border to delay their advance while the massive Chinese army mobilized. The Chinese had (and still dont have) any real interest in ICBMs or strategic weapons. Actually, during the Cold War, Russian and China were the two states who adopted a no-first-use policy (Russia abandoned this position in the 90s). The United States, and especially NATO, has repeatedly declared that the possibility of a preemptive nuclear strike is integral to an effective deterrent. The US also continues to reserve the right to utilize nuclear weapons in an offensive role against WMD stockpiles. This includes chemical, biological, and nuclear stockpiles. Here is a brief summary of the Obama administration's stance on First Use, and here is where it was under Bush. For a longer historical perspective, you could look into [First Strike!: The Pentagon's Strategy for Nuclear War By Robert Aldridge](he Pentagon's Strategy for Nuclear War). That book explores in some detail the shift in American policy during the 1980s from an overwhelming second strike, to a potent first strike capability. I would argue that the "Reagan Doctrine" of nuclear weapon usage still dominates nuclear war planning between America and another nuclear armed state, see: Russia.

4. ICMBs are located in strategic locations in the interior of the United States. They are in isolated and sparsely populated areas (make sabotage harder, as well as limits collateral damage). Since ICMBs are orbital weapons, range isnt much of an issue, for the ICBMs. A major consideration was the prospect of Soviet SLBMs, or Submarine missiles. These weapons had a range of a few hundred nautical miles, but could be launched stealthily and hit within a few minutes of their initial detection. Thus, the major CnC bunkers, as well as the ICBM silos themselves, were located as far into the American interior as was possible. Here is an image that shows where the major SAC bases were in 1988. Some of these bases have been decommissioned, especially as America has signed multiple reduction treaties with Russia.

5. Russia's plans are a bit more ambiguous than American plans, which are themselves still pretty well buried (understandably, the Air Forces doesnt like to talk about the details of its nuclear strategy, especially when it comes to ICBMs and their specific targets). But generally, Russia's forces were designed for an overwhelming second strike against industrial and population centers (see: cities). Russian ICBMs were notoriously inaccurate when compared with their NATO counterparts, and were thus unsuitable for anti-silo work. Instead, Russia planned to destroy the major population centers of NATO and the US in retaliation for NATO's preemptive strike (this is the basic premise of MAD). Also, depending on the situation on the intra-German border, the Russians would have also likely used tactical, theatre, and strategic weapons on the European continent to disrupt NATO's conventional forces, destroy their material reserves and air bases, destroy political and strategic headquarters, and generally prevent NATO from engaging in an effective defense of West Germany. Thus, in addition to most of the cultural and social centers of western Europe, most of the German and BeNeLux countryside would have been attacked an irradiated during the strike.

A good overview of the planning for strategic nuclear war is Lawrence Freedman's The Evolution of Nuclear Strategy. It is currently one of the only books (that I am aware of) that analyzes nuclear strategy from 1945-modern using any sort of historical method. Unfortunately, many of the books Ive read tend to be more positional, and recommend policy as its ultimate goal (First Strike! does this).