I really enjoyed this book. It was full of really interesting adventures by the author, and the part of living in the van actually only took up a few chapters at the end. I could see some parallels in how he described his spartan living, and even made tables to show how it worked out financially, which parallels Thoreau's original work (as best as I recall all these years later).
The author's note at the beginning assures us that everything is true and that some things were shifted around for the purposes of good storytelling, and you might be able to pick that out (I had a feeling a few times that the timeline didn't quite work out with what he was telling us). In spite of that, I got a lot of enjoyment on reading this book, and though I am fascinated with the amount of asceticism he has achieved, I think my approach would be less like Thoreau, and more along the lines of a co-housing arrangement. (I'm still working on convincing a few people of that.)