Articles about high-level subjects can be created, named sensibly, in the main namespace. For all articles pertaining to a specific ARG, a separate namespace should be created.
An ARG may have sub-namespaces underneath it for clues and similar large groupings of items, such as 'Clues'. Use these sparingly, only where really necessary.
This_Arg <- this is a page as well as the namespace This_Arg:Timeline This_Arg:Summary This_Arg:Clues <- this is a page as well as the namespace This_Arg:Clues:The_Golden_Apple This_Arg:Clues:The_Dancing_Frog That_Arg:Timeline That_Arg:Summary