It’s my understanding these nukes are tacticals, not big strategic devices, so they probably aren’t all that big. You can probably fit a few of them into a single truck.
Getting those nukes from their bunkers to the flight line might be tricky, but only if we let the Turks see what we’re doing. I’m convinced the Turks want those nukes to stay, and not for deterrent effect.
It seems you are more accurate than I am on this subject of size. (Each B61 is 11.8 feet long, 13 inches wide and weighs approximately 700 pounds.). Not too big to move but too big to conceal. They only have to detect one being moved without clearance. Another one of those Cold War good ideas that doesn’t look so good in light of changed circumstances.