Definitely visit the Mont St. Michel (island) after the tour buses leave. So a great time to head out to the island is mid afternoon (ie. get there by mid afternoon, don't leave Bayeux at that time). By the time you get to the old island itself the crowds will be thinning. It's a bit of a climb up to the monastery, but the views are incredible as the great history and beauty of the place. Just be sure you don't delay visiting the monastery too long (believe it closes at 6 pm but double check when you go). Also, there are often evening concerts to be enjoyed at the monastery, but you'll likely be tired and ready to settle in for the evening and rest after your day's visit.
We stayed at a small hotel on the east side of the causeway bridge (near where the tourbuses stop), which was fine. Le Relais du Roy. Nothing too fancy, but reasonably priced when we visited and you can drive onto Causeway area to park if you stay here. This hotel had a wonderful restaurant which we really enjoyed (try their appetizer seafood platter -- absolutely amazing!) Advantage of staying here is that you get to see Mont St Michel lite up at night, and can head out there at sunrise to see the early morning light on at as well. Know that will appeal to the photographer in you.