She must either cycle, or walk, or climb, in order to keep at bay the nervous dread with which her visit to Trenby had inspired her.

It had given her a picture of Roger's home and surroundings--a brief, enlightening glimpse as to the kind of life she might look forward to when she had married him.
It was all very different from what she had anticipated.

Even Roger himself seemed different in the environment of his home--less spontaneous, less the adoring lover.

Lady Gertrude's influence appeared to dominate the whole house and everyone in it.

But, as Nan realised, she had given her promise to Roger, and too much hung on that promise for her to break it now--Penelope's happiness, and her own craving to shut herself away in safety, to bind herself so that she could never again break free.
Her unexpected meeting with Peter the previous evening had shown her once and for all the imperative need for this.