Is it possible to get a reasonable train connection from Tours or a close station and get to Mont St Michel and then from there to Bayeux. Thanks
It's possible but takes at least five to six hours. And for you to decide whether this is reasonable, go to this website: clickand input your starting and ending destinations, enter 0600 as the time, the date does not matter for your purpose, then click search and the schedules will come up. It's a combination of train and bus to get to the Mont.
TGV trains go from Tours to Rennes, with a change in Le Mans. from there you take a bus, which conveniently leaves from the bus station right next to the train station (to the left as you look at the train station, called gare routiere). To get to Bayeux, you can take the bus back to Rennes, where there is a direct Rennes-Bayeux line. Just an FYI- if you are doing this on a Saturday morning, consider stopping in Rennes for their huge and fantastic produce market (take metro to St Anne, then walk down rue saint-michel until you see it)
This part of your trip is really a good candidate for renting a car, either in Tours or Rennes. It will make getting around that part of Normandy much easier and help you to make the most of the time you have there. You can return it in Bayeux or Rouen or any other city in France.