Friendship, resourcefulness, and sailing, too Arthur Ransome's Swallows and Amazons series has stood the test of time. More than just great stories, each one celebrates independence and initiative with a colorful, large cast of characters.
In The Picts & the Martyrs, those two Blackett sisters are back at it again, and Nancy is right there in the thick of it. Their mother (doubtless suffering from exhaustion) has gone off sailing in the North Sea with Captain Flint on a rest cure, but she has allowed her two daughters to stay a fortnight at Beckfoot on the lakeshore with their trusty cook. She's also permitted their two old friends, Dick and Dorothea Callum, to come up for a visit. But when their redoubtable Great Aunt (aka G. A.) hears of their abandonment, she's horrified and off on the next train.
The Amazons are dismayed; not only will their solo holiday be ruined but now they'll have to hide their two guests in the woods in an abandoned shepherd's cottage (where they'll be forced to live off the land like savages, ergo "The Picts") while they'll be required to dress up in white pinafores, practice the pianoforte, and recite reams of parlor poetry aloud (ergo "The Martyrs").
The entire Swallows and Amazons series is for children or grownups, anyone captivated by a world of adventure and imagination, exploring and setting sail.