My adult daughters and I are flying in and out Paris late May to mid June. We will spend some time in Paris and we are visiting a family friend in Loire Valley for 4 nights. I had thought of going south after Loire, but my daughter wants to see Mont Saint Michelle. It seems so out of the way. What would you recommend on how to fit in Mont Saint Michelle. Also, what itinerary would you recommend? Should we fit in another country like Spain?
We just took the train from Paris to Rennes and picked up a rental car at the train station and drove to Mont St Michel. We stayed overnight in Pontorson. You could also stay on MSM. Lots to explore in the Brittany region.. Then take the train from Rennes to your destination in Loire Valley.
You might reflect on whether you will need or want your own rental car while in the Loire. (I mean, in the U.S., in any suburb, you need your "host" as a chauffeur to do ANYTHING, which might eventually be a burden, for example. I'm not "urging" you to rent a car, but it is very hard to "do" the Loire valley without a car for every moment you are there.)
Both MSM and, say, Avignon, are quite far from (say) Tours, which has excellent train service. Have you looked at Google Maps? Although it is not next door, many people combine MSM with Normandy in general, or the D-Day beaches if that happens to be very important to them.
I have no opinion on whether MSM is more important than something to the south. But I'd mention (see first link below) that nice places like Fontevraud Abbey, are on the way to MSM. I also like Vitre a lot, both as on the road visits.
https://community.ricksteves.com/travel-forum/france/normandy-brittany-thoughts
https://community.ricksteves.com/travel-forum/france/normandy-brittany-loire-in-june-and-july-2024
Beware:
We wanted to spend the night in MSM but the weekend train schedule made it difficult. Make sure you are reading the train schedule for the correct day. We spent a few extra hours in Caen due to the "weekend" schedule" that I had failed to notice.
You don't say where along the Loire Valley your friend lives, so it's hard to know how "out of the way" Mont St Michel will be. Even at the closest, it would take several hours. But it's a unique and unforgettable experience, so I would say it's worthwhile to make the trip. It certainly isn't on the way to Spain, but if you visit other places in Brittany or Normandy, Mont St Michel turns out to be to along the way.
What are your interests? What other places were you planning to visit? How long will your trip be? Perhaps people on this forum can suggest places you'd find worthwhile on the way to and from your friend's place and Mont St Michel.
I don't understand, you think MSM is out of the way from the Loire but are considering Spain? Why don't you do Normandy? You could hit MSM for one night on your way to Normandy and then spend a solid 3 days in Normandy or more if you have more time. A day on the D-Day Beaches, Bayeux has the tapestry/cathedral/WWII museum or lace museum, you could do a day of the WWII museums, Caen, Jumieges, Rouen, Giverny and more are all options. It depends on what you like.