Red Army = most effective force !

[Marcello]

"Drains, covered sewer entrances and culverts can be packed with explosives to disrupt paved surfaces if you don't have time to pierce the surface."

Sewer entrances are available only inside cities. Culverts and such will not be conveniently sited in the best places for demolition. You need to plan in advance for identifying the locations and which demolition team must go where, they must be reasonably accessible in order to emplace charges (not filled with water or too small to enter etc.) and when all it is said and done it will be a limited damage that engineers can repair quickly. I have no idea if it was even taken in consideration.

"There was also the debate that certain NATO forces had stockpiles of arms that would have been released to the German population in major cities, arming hundreds of thousands of civilians."

It sounds pretty useless to me.Most of the people will either be fleeing towards NATO lines (from what I have heard, NATO planners considered it a big problem, as they would have created traffic problems for NATO columns plus those civilians had to be fed and sheltered putting further strains on logistics), hunkering down or otherwise too shocked to mount anything resembling a guerrilla campaign in the first few days when it will matter most.

"You don't have to drill through the tarmac if you can just go through the side through the packed earth. Highways are quick, but hard to get on and off, especially if the off-ramps are taken out. Units on it will be sitting ducks with very little cover or escape options."

There are others places that highways can be entered or left, especially for the combat vehicles. Service areas may have connections with the road network, there are often dirt roads within reach of highway in cultivated areas etc.. This quite beside the fact that taking out a significant numbers of off-ramps is quite a lot of work.
It is not like drilling thought the tarmac is the only problem. Even in the earth you still need to dig a lot of deep holes, or otherwise the damage will not be sufficient.The practical experience with bombing runways that I am aware of has shown that paved surfaces are more difficult to damage and quicker to repair than many (included myself before I found out) imagine.

"digging of deep trenches to block trucks"

If you have ever seen digging trenches in paved roads, you would realize that is not very practical.

"blowing up (high) buildings next to roads"

Outside urban centers that would be a pretty rare option.

"and then we're not even mentioning the use of nuclear demolitions or persistent chemical agents"

Nukes, well you are opening the pandora box. Using chemical weapons would be the best Christmas present you could give to the soviets. You can then sit back and enjoy the show of soviet chemical warheads missiles falling on NATO airbases,with the effect of massively cutting down NATO air forces sortie rate. This was a substantial concern for NATO planners back in the days.

"The road range is problematic the moment you have to go off-road. Even more problematic the moment you have to fight, as that includes lots of dashes to the nearest cover, reversing etc"

I got the impression that when the soviets specified design ranges for their vehicles, they did so with certain key objectives in mind. Yes, those 600 something km might be cut down to 400 something practice but I think this was aknowledged. If anybody has a map with NATO airbases at hand I think we might find something interesting.