On our first ever trip to France, we plan to visit the Loire Valley and beyond by car. But first we will spend some time in Paris and want to see Versailles and Mont St-Michel. The question is how to sequence this efficiently. Do we take the train to Versailles then rent a car and drive to Mont St-Michel and then down to the Loire Valley. Or do we day trip to Versailles and train over to Mont St-Michel and then drive to the Loire Valley, or take the train to the Loire Valley and then rent the car. Etc Etc. The options are many. Does anyone have a recommendation on how to do this efficiently and not drive in dense city traffic? From the Loire Valley we plan to continue south.
Personally, I'd suggest a day-trip to Versailles on public transportation as part of my stay in Paris. Once you're ready to leave Paris, take a train out to Caen, rent a car there, and then drive the rest of your itinerary in a loop heading southwest to Mont St.-Michel and eventually south into the Loire Valley.
The specifics of what you'd like to do from there would determine whether to keep the car or drop it at someplace like Tours and continue by train. But for the Normandy and Loire Valley portion, a car makes a lot of sense.