Le Mont-Saint-Michel is an island, in high tide, and a vast land, in low tide, sitting in the outskirts of the Normandy region. When the tide is low, you could walk around the vicinity and sink your toes in the sand, just be careful, there might be sinking sand. I would recommend going early to find parking and beat the rush of tourists. You can walk from the parking lot to the entrance door which takes about 30 - 40mins. Or you could take a free shuttle bus which takes 5 - 8mins.

So, if you do walk from the parking lot to the front doors, I recommend comfy shoes. Be prepared to walk the whole entire day and warning: there are a lot of stairs which are pretty steep (I felt like I did a stair master workout). 

I suggest to bring food, snacks, and a lot of water because touristic places are expensive, of course. But if you do have some money to spend, there are quite a few shops and restaurants around.
If you need to use the loo, you have to pay. When I went it was 0,50 centimes.

When I went it was the high peak summer season. The weather was hot and humid with a ton of tourists. I will definitely go back during the high tide when the city is surrounded by the magical waters of Le Mont-Saint-Michel.

Talk to you again soon,

Charmaine