Advice for 7 days in Brittany and Normandy in June

We stayed in Bayeux last Sept for several days. The cathedral and the Bayeux tapestry were excellent sites. The town is fun to walk around. You can easily drive to the D-Day beaches from Bayeaux as a day trip. From Bayeux we traveled to St Malo, which I would highly recommend. You can then visit Dinan from St Malo. I am glad you won’t miss Mont St Michael. It’s amazing. You can drive along the coast from there and possibly end up in Rennes. It has a lovely city park and several hundred timbered houses that are very old. It is also a town for strolling. We really enjoyed Brittany.
Enjoy!

Everything Susan said is true. The only thing I would add is that Rouen, Honfleur and Grisors are at one end (NE) of Normandy. Mont St. Michel, Dinan and Rennes are at the complete opposite (SW). All of these places are at extreme ends of Normandy. . Bayeux is somewhat central as far as Normandy goes, but there is no great way to get between them. This is a reason I highly recommend a car in this area. Re-reading your post, you say you arrive in Rennes, and then go to Utah beach, and then go to MSM. That is a lot of backtracking. If you arrive in Rennes, go to MSM and Dinan while at that end of Normandy. When you leave, you could go to Bayeux, Utah Beach and possibly areas farther afield. Because of this I have not yet been to Rouen (it is on my list for a trip from Paris to the Normandy Beaches this summer). But since you asked what to cross off, I would pick Rouen and Honfleur. They are furthest away from the places you have indicated you will definitely go—with the exception of Grisors...

I would leave Rennes immediately upon arrival - I do not find it particularly interesting vs the other locations you list.
I would then pick a base near Mont Saint Michel (maybe somewhere between Pontorson and Cancale) and stay for a few nights, 4 perhaps, to visit the Mont, Dinan, Fougères. St Malo is worthwhile too. Doing so, you wouldn't sleep on the Mont, but since you have a car you can stay there as late as you'd like.

Then, I would move to Bayeux for, say, 3 nights.

And I would stop in either Honfleur OR Rouen on the way from Bayeux to Gisors. Honfleur needs less time than Rouen, it is a very picturesque harbor and little else, but still very pleasant on a sunny day. Rouen is a better stop on a grey day, there is easy parking right at the cathedral.

Balso- you're advice makes a lot of sense. I just did the drive time check. We were going to stay in La Caserne anyway to avoid having to deal with suitcases going up and down narrow winding stairs in the hotels on the island of St. Michel (everything I can find says narrow winding stairs which are a no go with suitcases for me).

So it's about an hour from Rennes to La Caserne. And about an hour from St. Michel to Dinan. And an hour from St. Michel to Fougeres. If there's time, I'll try and throw in St. Malo.

Thinking about making Bayeux another base before heading off to Gisors. I'm thinking I may go see Rouen from Gisors where we'll be staying with friends. It's taking shape!

If you found a place you like in La Caserne, then yes, it is a good base to tour the area! Driving is really easy in these parts.

And from Gisors: if you drive to Rouen, make sure to pass by Lyons La Forêt. It takes maybe 30-45 minutes to walk around the village, but it is perfectly preserved. Worth the drive from Gisors even if you do not make it to Rouen.
Another beautiful small village not far from Gisors is Gerberoy. Giverny and La Roche Guyon are also within reach, and so is Les Andelys with its ruined castle. You won't have time to see your friends ;)

Balso- lodging near MSM is interesting.......Hotel le Relais du Roy is closed, I believe for renovations. And if the most recent reviews are accurate in Trip Advisor, long, long overdue.

This seems a reasonable alternative - it is what it is: not atmospheric but at least clean and comfortable.

https://www.tripadvisor.com/Hotel_Review-g196646-d251441-Reviews-Hotel_Mercure_Mont_Saint_Michel-Mont_Saint_Michel_Manche_Basse_Normandie_Normandy.html

I've looked at AirBnBs but they seem to either want a whole week or they're so far away you need to pay for parking.