GaME is an editor with support for Game Master Emulation (especially Mythic, see http://wordmillgames.com) and some hopefully useful feature to keep track of threads and characters, roll dice and organize the solitaire-rpg session into scenes.
The editor has been designed to be used without a mouse (although of course you may use a mouse or similar devices if you like). Every feature is availabe via keyboard shortcuts or by calling up the central context menu.