6 full days in Paris... would Mont St Michel be out of the question?

Mont St Michel is an experience that I wouldn't want to squeeze into one day! Rick suggests going early or late in the afternoon, early evening, and for a very good reason. About 10-10:30, the tour buses roll in, and the island is swamped. Also, it is quite a ways away from Paris, and getting there is not direct; I think the train drops you at Pontorson, 15 minutes away (taxi), but the train takes four hours.
If you are willing to sacrifice two days out of your six in Paris (and sacrifice it would be!), you could take the train, stay overnight on the island, and then return the next day. We stayed in a hotel, Le Mouton Blanc, on the island, and it was magical, in the evening, when the lights went on, and the crowds disappeared.
Betsy

Echoing the above statements, it could be done (plenty of tour buses make the trip daily), but you'll be there during the most crowded part of the day, and you'll miss Mont St. Michel at its best. Consider staying the night, and visit the abbey early in the morning before the next wave of daytrippers invade.

Hazel, there are tours from Paris to Mt. St-Michel that use the train. You are picked up from the station and taken to the abbey. It is a little pricy--$304.00 but also includes Dinan and St. Malo. You can find more information at www.linkparis.com