Walden is nothing like Life As We Knew It bu Suzanne Collins. The former has a positive outlook nearly the entire time of its duration, while the latter incorporates pessimism into everything that happens. Every. Single. Thing. Miranda was always whining about how the world was ending, how hungry she was, how unfair her mother was, how ungrateful she thought of herself, and on and on and on. It's not necessarily a bad thing, but it's on the whole other side of the spectrum from Walden. Thoreau was always bringing up how grateful he was for his lifestyle, perspective, and more. He hardly ever looked down upon his choices, and surely never pitied himself for making them.
However, both are similar in that they lack action. Honestly, nothing really happens in either story. Life As We Knew It is a bit better with the plot. But Thoreau uses his lack of plot to his advantage. He preaches more of life lessons, and what he learned from his experiences with nothing. Miranda also bases her journal entries on the fact that practically nothing happens to her. They both lose contact from a majority of the outside world. All in all, they were both enjoyable books. At least to some extension.