The interplay between text and illustrations in this story is important, as it is a tale about imaginary play.  Basically, it is the story of two sisters having a campout in their back yard, but that’s just on the surface.  In the world of imagination, it is a princess setting off with her panther to cross deserts and drink from wide blue lakes and pitch their silk tent in the night to keep out the leaf-snakes and the owl-witch and the frog-monster.  Throughout all the adventures, the princess (i.e. big sister) is brave, and the panther (i.e. little sister) tries to be.  In the illustrations the reader gets to connect reality to imagination:  the wagon on one page becomes a camel on the next, the wading pool becomes the sea, the grand red silk tent becomes a blanket thrown over a rope, etc.  A good story for encouraging imaginary play and acknowledging that backyard sleepovers can be a bit scary if you let your imagination run loose.