On our recent holiday in Portugal we were caught out by volcanic ash, and returned to Ireland via car to Cherbourg and boat from there to Rosslare. We spent four days driving back, and stopped in some very nice places. Avranches is an historic town in Normandy, its park has dramatic views on to Mont St Michel.
I see you idea but hardly the mont. Perhaps you could be more daring in you shoot and try a tele (yes even for landscapes) and vertical like the last photo in order to have just the river and the mont. But the light will still be poor.