To collect the Book of the Dead achievement, you have to get all 10 Ghostpedia entries in Act 1. Thing is, to get one of the entries you have to let the Young Genderuwo ghost kill you... which invalidates the YOLO achievement, which requires you to beat Act 1 without going to Limbo. It's certainly annoying; as much as I enjoyed this game, replaying Act 1 two or three times in a row for achievements isn't my idea of fun.

By complete coincidence, i've managed to stumble upon a glitchy way to avoid having to die.

• Get all three medals during the daytime exploration sequence
  
• Back out into the streets during the night time, before entering the school
  
• Defeat the Pocongs in the park, but DO NOT defeat the Motorcycle Pocong
  
• Head back to the car to find Young Genderuwo in the way
  
• Defeating Kun-tilanak under the gate might be optional, but do it anyway

Once you're there, get as close as humanly possible to the Genderuwo without triggering the death animation and just wait; you should be a few feet from the hand. In doubt, don't get any closer, it doesn't matter that much, because it either works or you can try again.
Thing is, as long as you're standing there, the Motorcycle Pocong should eventually drive by and knock you inside the Genderuwo's "kill range". The knock direction seems fairly random, as much as I've tried, so if it knocks you the other way just get back to where you were and try again.

If done correctly, you should now be inside the 'kill range' and unlocked the Ghostpedia entry, but you won't actually trigger the animation that sends you to Limbo. In fact, this glitches the Genderuwo quite badly, as it seems like it triggers his kill animation without actually killing you, so he's stuck in a harmless state. Here's a not-so-useful screenshot of me just standing close to the frozen Genderuwo, way past the point where he'd kill me.

Please let me know if this also works for you!