Mont Saint-Michel on a sunny day doesn't need any retouching.

We were so lucky. It was rainy in Paris for several days, but it was sunny on the day we went to Mont Saint-Michel. Mont Saint-Michel is more than 4 hours away from Paris by car. The advantage of joining a day tour is that you don't have to transfer between different modes of transportation, and a tour guide is provided. The disadvantage is that the itinerary is very tight. You leave at 7:15 am and return to Paris after 9 pm. If you want to have fun, you don't have time to eat a proper meal. If you want to eat, you don't have much time to have fun. So, if possible, you can stay there for one night and visit the nearby towns.