Hi and thanks for ideas!
Google Drive or Dropbox are possibilities. Version control probably isn't an issue with one person coding, or my wife coding totally different stuff. Usually.
Dropbox at least keeps a physical copy on all machines, so things work fine if the net is down/slow.
Where/how do I tell the IDE that stuff is not In The Usual Place??
Rob, in my 'standard' installation terry/arduino contains terry/arduino/libraries so I THINK I only have to tell IDE where the /arduino root is??