Paris to Mont St Michel

No real language barrier. Memorize a few basics and polite phrases, you will be fine with your upper-midwest English. Renting a car is not difficult (book it as part of your planing, don't wait until you are there). Navigating and driving is not difficult as long as you avoid central Paris or other city centers. There are a few things that are different (eg: signage, how directions are expressed...you won't see things like a road number followed by "North", instead you'll see city names, that is Road X in the direction of CityName...this may seem disorienting at first but you will catch on; a GPS that you know and are already used to using (brought from home) will help.

Make sure you learn the road signs and traffic laws. Both will be significantly different from back home.

Road signs are the same (90%) throughout Europe, but they are mostly symbols, not words. So it doesn't matter if you don't speak the language, as long as you know the symbols.

Driving in France is not difficult even for newbies as long as you know how to read. Both French and English are derived from the Latin Alphabet and so letters will look familiar to you unlike let's say if you were driving in Russia. You'd be surprised at how much of a difference that makes in feeling comfortable behind the wheel. Spend a little time reading up on French road rules and learning the meaning of the symbols and you will be good to go. As to your planned trip, I would not do it the way you have planned it but not because it is daunting more because I think it's too much time spent driving when you could do the same trip by train in half the time. But that's just me and my opinion which is only worth what you paid for it. I'd do Versailles as a day trip from Paris and Le Mont Saint Michel as an overnight trip by train in the middle of my time in Paris. And I might do neither depending on how many days I had allocated to Paris for the trip.

Here is a lot of information from our host about driving in Europe. It shouldn't be too difficult for American drivers. Auto Europe is a good way to shop for and reserve rental cars, a US-based broker that sets you up with the actual rental company (Hertz, Europcar, etc.) If you'll need an automatic be sure to say so, expect to pay more and have fewer choices. GPS is a good idea, along with a map. If you can bring one from home that will help, but you may need to buy and download a Europe map for it.

Via Michelin is helpful for planning routes and estimating driving times, though it doesn't take account of stops and traffic variations. It shows a minimum 4 1/2 hour drive from Versailles to MSM. That will take all afternoon, so your morning visit to the palace will need an early start. It also shows a 5 hour drive from MSM to CDG, leaving only a few morning hours to see the Mont. These routes take you through or near a lot of interesting cities and sights in Normandy (Rouen, Honfleur, Caen, Bayeux, D-Day beaches) that you won't have time for unless you add a day or two to this road trip.

For me, this would be a lot of driving to see one, admittedly iconic, sight in France. But I don't know how long your overall trip is or what your priorities are. Hope everything goes well!

That's a lot of driving for just one sight/1 nite. What will you do with your luggage while visiting Versailles?

Our visit to Versailles was a long exhausting all day affair- we left Paris at 8 am returned about 6 pm. The place is huge - I can't see cutting time there short to drive 4/5 hours to MSM. Nor would I want to drive that far after the visit. We spent a lot of time enjoying the gardens, hamlet, having lunch etc. Enjoyed that actually more than the palace itself
Maybe do Versailles as a day trip instead?.

Driving in France is easy- we rent thru AutoEurope for all our European rentals. Be sure you get your IDP (from AAA office in states). If you need an automatic you have better chance of obtaining one if you pick up at an airport or larger facility. We picked up at ORLY on our recent trip. Very easy.

Honestly I would look into a bus trip to MSM from Paris- they must exist? Actually they do- here is one example:
https://twitter.com/Jordanfabian/status/1110217245274320896

Maybe if you share your Paris itinerary we can help you pinpoint a better way/day to see MSM?

Because it's your first trip to Europe, you should glance at our host's travel guide for France or Paris - or look at it in your public library. He's really helpful for first timers.

I don't know if you can afford to blow off your last afternoon/night of vacation at an airport hotel. Many people take a cab from their hotel to the airport, but it depends on departure time, of course. You might get more nuanced advice if you post your rough itinerary. But you certainly don't want to take the car into the city of Paris itself - that would be a nightmare. I am glad you're not trying to do MSM as a same-day trip from Paris, but this is an ambitious plan. I wonder if something closer might be better, and by train. I find it interesting that you chose MSM over the D-Day Beaches, which are asked about every week on this newsboard. Because none of my uncles served in Europe, I wasn't drawn to Normandy until we'd been to France on several other trips.

Personally, I liked MSM, but I don't know if it's worth the time away from Paris, where we spent seven days on our first trip to Europe (a week each in London and Paris.) There's nothing just like MSM right nearby, but you can see medieval buildings in Paris. The drive to MSM isn't challenging, it's just long, and on controlled access highways, boring. Can you think of some aspect of France that interests you that you could ride a train to? I mean, art, or Joan of Arc, or wine, or food. Do you have ancestors from Europe? I admit that Strasbourg is far away, but it's less time, by easy, more scenic train than the car time to MSM, and it's just as ... er ... exotically antique, in its own way. Closer to Paris, you have Chateau Chantilly and Monet's Giverny.