[Marcello]

"You can just as easily take out large sections of roads, crossroads etc with modern engineer and demolition equipment so as to make them unusable (as roads etc) for quite some time."

I don't know. You can put some demolition charges on the key points of a bridge and continue to use it until the last minute, then blow it up. Railroads are easy to take out too. But how would you destroy a paved road? Explosive charges? You will need to drill a lot of holes. Buldozers?
Tarmac and the underlying layers seem pretty hard for your typical dozer blade to negotiate quickly. At any rate every time I have seen it removed specialized equipment was used.And that hardware was comparatively rare.
I will also note that from what I remember from their doctrine the soviets emphasized the use of forward detachments to seize key passage points.That could be bad news for a bunch of engineers trying frantically to fill a road with holes.

"Tracked vehicles and all terrain wheeled vehicles can, but trucks will quickly become stuck"

I will note that most soviet vehicles have comparatively long unrefueled cruising ranges (like in the case of river fording it was accomplished with trade offs, see BMP-1 rear doors). The T-62 and the BMP-1 can, on paper, do more than 600Km. The T-55 can, on paper, do 600km, and so on.Those are not a trivial distances in Western Europe. I suspect that it was done on purpose to enable them to quickly seize NATO airbases and other key objectives without the hassle of dragging fuel trucks along. Which is not to say that trucks will not be needed but that "reasonable disruption" might be called in question. Again the specific historical period is important.