The Fortnight in September by R C Sherriff

I found this hard to read initially, because the family's anxieties over their journey were so acutely realised. But once they had reached Bognor, their pleasures were equally convincing. The family is on the cusp of a change in the way they take their holidays, partly because the two older children are now adults starting to seek their own pleasures, and partly because holidaymaking itself is changing - Mrs Huggett's shabby B&B will no longer do. This change, and the family's dawning perceptions of it, give the novel its tension and interest.