Driving from Mt St. Michel to Versallies - need advice

Are you committed to driving? It can easily be done by public transportation, which might be easier when you are jetlagged. The train from Paris to Pontorson is about 3 hours. If you want to continue onto MSM, you can do that via a relatively short bus ride. And Versailles is an easy train ride from Paris.

I would be more concerned about the route as a whole. The part between Pontorson and Alençon is two lane running through places, roadworks and trucks really slow down the pace. The needed time Google tells is theory, 4 hours for 330km is to my opinion way too optimistic, you can think more between 5 to 6 hours from start to finish. I think there is a risk of getting fed up after a while taking the N12.

If you really want to drive you can drive along the A81 and A11 (E50). Places like Fougères, Vitré, Le Mans (besides the famous racetrack has a lovely historical city centre) and Chartres are worth considering a stop.

It's usually us Americans who worship the freedom of a car. I'll just observe that Versailles is a very easy outing from Paris by public transportation. So I wouldn't "waste" a day of car rental on it. You do need a car for the Cider Route, Vitre, Dinan, public gardens (numerous in Normandy), and so on. A lot of people might visit Monet's garden on this trip, but you haven't mentioned art-related stops. I found the approach to MSM to be a rather touristy roadway. But nothing beats staying with locals, anywhere. Presumably they will have the MSM parking lots scoped out already for that visit, and the tides if you care about that. (We didn't.)

If you can't board a train AT CDG that goes to Caen, I would proceed with your plan. We were disappointed with Fougeres, but as noted there are lots of nice towns to visit. Note that there is a "Canadian section" of the Normandy D-Day beaches, if that interests you. We enjoyed Vitre, but didn't have time for the Cider Route. Note that European vacations begin in August, increasing crowding and perhaps producing a few restaurant closures.

Thank you all for the reply :)

Our family had considered using transportation to Pontorson, but decided to rent a car due to my aunt's physical condition who lives there. I think I need some caffeine to overcome jetlag when I drive.

Unfortunately due to limited time, we are going to skip locals (other than MSM) in Normandy area before going back to Paris. It is good to know that condition of local road (such as N12) is not guaranteed - may have to take A81 instead.

So our plan would be:

7/30 (Thu) - Arrive and pick up rental car at CDG around noon, drive to Pontorson through E5/A84

7/31 (Fri) - Stay in Pontorson, visit MSM

8/1 (Sat) - Depart Pontorson (in the morning) - take A81 road (or even E5/A84 that pass through Caen) to Versallies (hopefully arrive around at lunch time and visit the castle/garden for around 5-6hrs) - Arrive at accommodation near Orly airport around dinner time (also drop off rental car at Orly airport)

I understand our family will miss a lot of places like Chartres on the way, but we would want to spend enough time in Versallies and Paris before continuing other journey to Austria by train.

I certainly share your desire to avoid driving inside the city of Paris. It does seem odd to be staying at an airport hotel for a visit to Paris, but I presume you have your reasons. I'd hate to have to take surface transportation twice a day while on my first trip to Europe. Likewise, the last time we were in France (travel from NYC area, US) we took the train from CDG to the Loire Valley and rented our car there. That way, I only had to spend two hours driving after a poor (to say the least) night's sleep on the plane.

Naturally you want to make the most of your time in Europe. You are the best judge of your comfort driving on little sleep. When we drove back to near Paris from Bayeux (not directly from Dinard, where we stayed for MSM and that area), the driving was just like limited access state highway driving in the northeast United States: Little scenery, vulnerable to construction, but better "highway food" than the US! Even if you have a chip-and-pin card, be ready with cash for tolls in case the card isn't accepted. Of course, you can put "Avoid Tolls" into your GPS, but that would be a much longer drive, I imagine.

Unfortunately your post has not yet turned up anyone who has driven through the Parc Naturel. I have trouble reconciling your reluctance to take what might be a scenic drive with the expressed desire to take local roads. I can tell you that we went on some really local roads in Brittany that were similar to English farm roads, paved but only 1.2 autos wide, travel in both directions! I would suggest that you use the Michelin or Google Maps websites to get some comparative driving TIMES, using both the most direct route, and routes with more miles but multi-lane expressways. Then you can make an educated decision. I have more experience with Google Maps, but they let you drag the route to another highway, and then it recalculates the (ESTIMATED) time.

Thanks Tim for sharing some road experience in France - since we would like to get to Pontorson asap when we arrive at CDG, so 'better highway food' sounds great!

Yes, accommodation near Orly airport seems a bit odd, our family have decided to stay there after a bit of discussion. Also it is very close to metro station (line 7, Villejuif Louis Aragon)

I also have used google streetview to get some idea how the road in Parc Naturel look like - looks like a plain country load, not too scenic (main reason to take a local road). The road looks like easy to drive but not wide so it might get slow down by construction/trucks as mentioned from the above... maybe I should skip going through Parc Naturel.

I think I got some rough idea now and probably share some experience once I come back to trip... Thank you all :)