May is a splendid time to be in Cormolain. The blossom is in full flurry, it's warm and the crowds haven't started to arrive.
To the south-west of St Lô is the ruined abbey at Hambye and just a little further on is the old town of Villedieu-les-Poeles, famous for its bell foundries. There are guided tours in English, at set times.
Even if you choose not to take one of the guided tours (or the timing is wrong, as it was for us), the town itself is still charming with plenty mediaeval courtyards to be seen.