Read Sam's note first
To open the documented door, first obtain the Cryptic Note from Sam. The note gives the number pattern 43_81; use that pattern as the clue for the door.
Connect the clue to Sam's quest
- Where should I use the note, and what related task comes next?
- Use the clue for the locked door associated with Sam's note. For the related Childhood Fear route, speak to Dan at the Town Store, then meet Sam at Greystone Estates; find Sam's Lucky Pendant west of the estate, meet Sam in the F3 Stairwell to clear rubble, offer 10 Spiritwood and 10 Leather at the roof altar, and defeat Mr. Wiggles.