While there are no available Sparknotes for the book "Into the Wild", CliffNotes does offer a short summary that is formatted similarly to diary or a journal. It is broken down chronologically into short blurbs, summarizing the protagonist's experience.
Usually, CliffNotes are broken down by chapter or section of the book, but this is a unique book with unique CliffNotes.
An example of how the CliffNotes summarize an event from the book is "July 6, 1990: Arrives at Lake Mead National Recreation Area in Nevada." Then it goes onto the next significant event, which did not take place until four days later.
In addition to using the CliffNotes summary to review for a test on the book "Into the Wild", there is also a film adaptation of the book. The movie, also titled Into the Wild, stars Emile Hirsch as the well-known protagonist Christopher McCandless. It follows McCandless as he graduates from college, leaves his friends and family behind, and slowly hitchhikes his way to Alaska to live alone in the Wilderness.
Although the most fool-proof method for passing the test on "Into the Wild" would be to read the book, the movie is very good and is worth the watch.