We've been to Paris and up to Normandy; now looking for tour that would take us to Mont St Michel & Chartres. Also St Malo. Other sites in the area would be fine. Looking for around 7 days. Prefer train travel over bus.
So, you are looking to sign up for a guided tour that goes to these two destinations? Please clarify. When you say you prefer train travel, that makes it sound like you want to arrange your own trip, not take a pre-arranged guided tour.
For the cathedral at Charters, you could not do better than the lecture tours conducted by Malcolm Miller, the greatest living English-language authority on the cathedral. Take the train from Paris and either walk or take a taxi to the cathedral.