[SCAR]

Originally Posted by Peter V. Dell'Orto

Not purely GURPS - just notes on how I do room notations for my megadungeon in DF.

Megadungeon Best Practices X: Room Writeups

You could use Word Styles with the Strikethrough format for old room data.
Create a Style with strikethrough (Old Room Data), and create a second style with Strikethrough and shrink the Font down to say 2 point, and may a very pale font (Virtually Hidden)

You can then select all text with the 'Old Room Data' style, and apply the 'Virtually Hidden' style to 'hide' the strikethrough text; or reverse to bring it back to visible.

[EDIT: I just noticed that Word supports a 'Hidden' property of the Font Format - so you could use a Hidden font style as the second style]