Looking for suggestions for a base in Brittany

Rennes has public transportation links for Dinan , St. Malo, and Vitre. For MSM you might need a tour. Visiting all of these places would be much easier with a rental car. Driving in rural France is not much different from driving in the United States - we have driven in France several times with no problems.

Take the train to Rennes to pick up your rental car. The road are so nicely maintained and it’s very easy to drive there. We just did it in April and it’s so much easier to get around to explore.

You have a wonderful trip planned! Enjoy!

Between Rennes and St. Malo I'd base in Rennes, especially if relying on public transit. Rennes is a medium sized town with a pedestrian-only core, a beautiful park (Thabor), a sizeable university-age population, and interesting architecture. Rennes will also have much better public transit connections. St. Malo is a small walled town on the water across the harbor from Dinard; we thought a few hours in St. Malo was plenty.

Brittany is much easier to explore by car and it isn't hard. With two people, one driving and one navigating, it is a cinch. Just scrupulously obey all posted speed limits. Autoeurope is a rental agent many people like; get the full insurance package for worry-free driving. With a car you could, for example, stay in Dinan and then drive to visit St. Malo and park in their large lot in the morning, have a late lunch in Cancale (famous for its oysters), then show up later in the afternoon at Mt. St. Michel as the bulk of the daytrippers are leaving. Spend the nite in a hotel across the bridge so you can park in their lot, enjoy how spectacular MSM is lit up at nite, perhaps another brief visit to MSM in the morning before you leave. I doubt you could do a day like this using public transit.

The Michelin Green Guide for Brittany covers just about every town in Brittany. Also request Stu Dudley's Normandy & Brittany itinerary; see https://www.fodors.com/community/europe/normandy-and-brittany-stu-dudleys-updated-itinerary-1670294/ We used these when planning our trip to Brittany a few years ago. You can also find many videos on YouTube exploring the area.

One other comment about your schedule, it looks like you have two half-days sightseeing in Brittany sandwiching two full days. Rick Steves often advises people "assume you'll be back" and considering your age it's likely you'll visit Europe again. Brittany is a large region and one could easily a week or more there (as you'll see if you look at the resources in the previous paragraph). But it's also not particularly convenient to just pop over to Brittany with 1-3 spare days on another trip. By contrast Paris is easily reachable and on some future trip, even if to a completely different part of Europe, you could connect thru Paris and spend a few days. If I was planning your trip I'd take some days away from Paris and move them to Brittany, seeing the skipped Paris sights in the future.

Thank you all for your responses! We greatly appreciate the time & effort you put into sharing your experience with us.

We are beginning to think renting a car won't be so bad, so perhaps we will end up doing that.

Bill G, thank you for all of your advice! We will reconsider our Paris itinerary and perhaps do another do in Brittany. I will definitely check out the guide & Stu Dudley's itinerary!

A couple of years ago, we flew into Rennes, rented a car and based in Dinan a couple of days. We loved Dinan. We then moved to the town next to Mont St. Michelle for one night, then to Bayeux. Driving was simple. We took the train back to Paris from Caen. The only difficulty we had was finding the rental car return in Caen. Have a wonderful trip,