Ken has said Roberta's design documents run around 500 pages long, especially in the later games. A person who worked with him back around 2003 as his site administrator and a co-worker with Talkspot saw the stuff and said the assessment was correct:
Ken: "Every Sierra designer had a different style, but, generally, they all produced HUGE design documents. Roberta's designs were usually 500 to 1,000 pages.
Typically, there were distinct steps to the design of the adventure games.
1) A two page story idea
2) A map showing the locations
3) A longer design document - perhaps 30-40 pages
4) Artists would get involved at this point
5) Character sheets - to show each character
6) Pencil sketches of each location
7) A much longer design document - perhaps 500 or more pages
For the 3d games we did later, it was even more complex."
An early KQ8 design note by Roberta: