If you want some sort of guide for reaching a specific final, I suggest you to check Steam communities; there are two detailed walkthrough for each endgame.It's quite unlike anything I've ever played before, the only thing that comes somewhat close is Deadly Premonition. I was sent on a quest to retrieve some old ladies' under garments and I failed the mission as a bird stole it from me the moment I actually managed to find the damn panties.
Initially I played it doing random side quests without any logic, but it was a "wrong way" to play it for me. I needed a reference guide to know what to do, when, where and what are the best choices for every dialogue.
A crazy game indeed and the sequel is even more crazy, in some aspects.