"They had a whole eight-weeks timeline laid out, with various people breaking various aspects of it as if by coincidence, and it would, as you speculate, have led up to that old charge they used in 2000, that Bush was a druggie."
I believe this is exactly right. Depending on how well the smear campaign went, they would have ended with charges that GW was an unstable risk for relapse, or preferably float a story that he had been back on drugs during his term in the White House.
CBS would of course have been in the middle of it all, coming up with carefully planted stories to move the saga along at critical points.
Smear campaign? Did I hear you say smear campaign? Why does the name Sasso come to mind?? That's his specialty.