I am searching for a book that I read in the early to mid-eighties – I believe the book was a 1960’s era book. A young girl moves to a beach house on a cape (maybe for the summer). Possibly the house across the cove was haunted or abandoned/isolated . What I remember most was that she had to climb down some cliffs at night and trek or swim across the cove in the ocean to get to the house. May have also included a brother or a local boy who had become a friend. Was she trying to save someone? Wish I had more memories but the climb down and swim across the cove at night are my most clear memories. Thanks.