Is there a way to display the basic room descriptor in a colour other than the default of red? It's just that red doesn't look too good against most background colours other than white.

Are you making your game through the QDK, or are you scripting the ASL in a text editor? (Or both?)

You can accomplish what you want by writing some custom ASL in the description tag of the game object. You can have a look here to check out how to do that. Quote from there: "[The description tag] overrides Quest's room descriptions by executing the script you specify here, or writing the text you specify here, rather than print Quest's default room description."

In other words, whenever you enter a room, whatever you specify to print here will show instead of what would normally be printed.

For more detail, see this