Jeanne Birdsall, The Penderwicks

Jeanne Birdsall, The Penderwicks. Four children on summer vacation at a country estate with a dead mother, affectionate yet preoccupied father, and rambunctious family dog. They have adventures, get into scrapes, stick up for each other and make new friends while facing all sorts of obstacles. Sounds familiar, right? The story is explicitly reminiscent of E Nesbit and Edward Eager and CS Lewis - and mentions by the children of really good books are themselves a tradition in these sorts of stories.