HELP on Beaches of Normandy and Mont St. Michele

To go to Mount St Michel on your own like I did take the train from Bayeux to Pontorson - Mont-Saint-Michel.
At Pontorson - Mont-Saint-Michel there is a bus that goes straight to Mt ST Michel. You will know instantly as you will see other tourists.

Similarly from Bayeux in front of the train station there is a bus number 70 that goes to the American Cemetery and Omaha Beach. located in Colleville sur mer as well as Point du hoc located in CRICQUEVILLE-EN-BESSIN.

You will know instantly as you will see other tourists waiting for it.

Here is the schedule for bus 70
Going:
https://www.busverts.fr//fiches_horaires/L70S2.pdf

Coming back the very last bus is at 18:47
https://www.busverts.fr//fiches_horaires/L70S1.pdf

Have you looked at Bayeux Shuttle?
Recommended in Rick’s Normandy guide book.
http://www.bayeuxshuttle.com/
They do full day and half day tours of the D-day beaches from Bayeux....I booked with them for later in October. They also run a shuttle to MSM but I am less familiar with that.

Are you a group of 9 or a group of 8?
Looks like Bayeux Shuttle might have some half-day tours available for your dates. You might pay less per person if you book a private tour with them instead of paying per seat for a shared group tour. If you don’t see what you need, you can email their office— they are very helpful.

We used Bayeaux Shuttle also, and thought they were great. We did one 1/2-day tour to MSM and another 1/2-day tour to visit various American sites for the D-Day invasion. The tour guide was extremely knowledgeable. Hopefully, they aren't booked up yet. Best of luck.