So here's a Google map of Llangelynnin.
View Larger Map
As you can see, the church isn't very far from the beach.
Hendre, Anne Clarke Morgan's residence, is a little harder to explain. There is apparently a house named Hendre across the bay from Llangelynnin. But it looks very new and is in the middle of a row of houses, so that doesn't make sense. There is another house apparently in Dolgelley on Well St. But the only town named Hendre that I come up with is in Mid-Glamorganshire. But that is quite a distance away and how would they have met?