I think the order in which the different elements of the book are introduced is crucial, as it leads to a lot of "aha!" moments.

> What put me off it is it just kind of reads like a rambling stoner conversation.

Yeah well, that book may not be your cup of tea then. The book _is_ rambling, plus a lot of the characters _are_ actual stoners/addicts/recovering addicts. But keep in mind that most of the book is in the third person, not in the first (as the first few pages would make you assume).