>>64159310
>The question is having used nukes how would they then achieve the rest of their plan
They wouldn't.
They'd reach the first line of cities in Germany (Hamburg, Hanover, Kassel, or rather the nuked ruins of those cities) but at that point they will just get stuck. Forget the Fulda gap, or any of the forces in Czechoslovakia/Hungary. They planned to nuke their way through Austria and then take Munich after driving up the radioactive Danube.
Everyone without a mask is on a 5 day timer due to radiation sickness, with a mask you're roling a dice wether you touch a branch that has VX on it (or the Soviet equivalent), and if you're fully suited up you're not moving fast, especially because you can't really cross groundburst ground zeros for a day or two even in a suit.
In your vehicle you have a day before you're out of fuel, and forget logistics because everything just got nuked and VX'd.
You can also roll a dice to see how many bridges and crossroads the Germans blow up before teh Soviets arrive, and how many of those that are left get nuked.
Also, NATO air power from French and British bases is not going away, unless the Soviets nuke those, too. AKA 'how to escalate to a strateegic exchange in one easy step', assuming the US didn't just activate SIOP already anyway.
Day 1 and 2 will be Soviet advances, by day 3 things will just start to come apart at the seams, by day 5 I wouldn't really expect anyone to be a coherent fighting force.
And to paraphrase On Thermonuclear War, no armmy in the worlld hhas the capabillity to deal with tens of millions of civilan corpses, whichh is what most people between Belgium, Poland, Denmark and Austria would become.