Where It All Goes Down
London and Folkestone, England, and (Late in the Novel) Boulogne, France
The journeys in Maisie are mostly inner. But for good measure—and to make sure that readers don't miss his point—James adds a real travel narrative into his story of self-discovery.
Maisie makes her way from London, where she has remained since the beginning of the novel, to France by way of the port city of Folkestone. And this journey really shakes things up; its effect is to say, "Okay reader, pay attention now," and attention is exactly what you'll want to pay. Because in Boulogne, Maisie herself becomes more attentive and alive, and that's a clue that her life is about to change forever there.
There's also the fact that all of Maisie's guardians, with the notable exception of Mrs. Wix, decide to flee London. Maisie's dear old dad goes to America. Maisie's mommy dearest goes to South Africa. And even Sir Claude and Mrs. Beale end up in France. This shows us that there are two kinds of voyages present in What Maisie Knew: the voyage of a girl's self-discovery (huzzah!) and the voyages that consist of running away from responsibility and Victorian morality.
And it's also worth noting that the Boulogne jaunt is put in this novel in order to underline not only the change in Maisie's life, but also the fact that she gets to then, literally, travel home with Mrs. Wix.