A few of you have asked me to post more information about day trips from Paris. Back in 2004 my first full-length guide was published, called "Paris & Ile-de-France Adventure Guide"(Hunter Publishing), which had a lot of information to lure you outside the periph, but alas a guidebook that old quickly becomes outdated.
But I can happily recommend another fabulous guide, Annabel Simms' "An Hour From Paris", with 20 itineraries in Ile-de-France, with maps and photos, accessible using public transportation. Annabel, who has been living in France for 18 years, personally re-visited every single location (with eagle-eyed friends in tow) for the newly updated version.
Have a crack at it before everything closes down for the winter (note: that was my Parisian superiority complex creeping into that last sentence; read it with a sneer to get the full effect).