Well, depends on how the Russians react. I would hope Clinton would be called on the Hotline with an attempt to figure out why WWIII would be just minutes away. And Yeltsin was apparently sober that morning.
So presuming we get all heck breaking loose, things end badly. Most of the northern US will be wiped out, especially east of the Rockies as the fallout from strikes in the Midwest settles across the Eastern Seaboard. Most of the southeastern US is also toast though the Appalachians might have some surviving areas, a few very large pockets especially. Texas is likely toast, but outside of Hoover Dam and Coastal California there are large parts of the Intermountain West that will still be intact. Europe will be in severe danger while the USSR itself is largely destroyed. Brazil, Argentina, South Africa, New Zealand, and Australia are likely the new Big Five with India and Pakistan possibly on that list as well. Watch for American/European refugees to flee south to civilization and set up expat communities. A new UN will be set up and nuclear weapons will probably be banned almost immediately. I would estimate 3-4 billion dead when all was said and done, especially if China collapses into civil war as its economy starts to decline. Japan and South Korea will probably be heavily targeted but *might* be able to survive In some form, especially Japan. The fate of Taiwan is also uncertain.
Look for eventual resettlement and rebuilding of the affected areas over time but the teenagers of that time will be in their late 30s or early 40s by the time life returns to some sense of normalcy. Internacine warfare will be a problem, especially as agriculture must reemerge and warlord states will come and go.
I generally agree. However, would the Russians even bother with a counter force strike on Midwestern missile silos if they believed the Americans had launched first? All those pretty nukes might instead be tasked to counter value targets, meaning that smaller settlements in the US and Canada will be plastered than would otherwise be the case. Instead of a 10% survival rate 5 years post attack, it might be 2 %.