Next year we're taking a 2 week group tour of Switzerland. Following the tour we plan a few days on our own in Switzerland followed by a possible week in Paris. It will be our third visit to Paris and we're ready to be more adventurous this time - rent a small apt and do most if not all touring on our own (public transport).
My question is about possible day trips from Paris. We've been to Versailles and Giverny. I'd like to see some of the chateaux in the Loire. Not sure how easy that is to do using public transport or walking. Other suggested sights? We like interesting architecture, scenery, quaint walkable towns, a little shopping, etc.