Maybe the first time we walk to the museum maybe there would be a cutscene where the neighbor peeks through the curtains and sees Quentin and closes it maybe it would be in 3rd person and a mix of 1st person, maybe it would show Quentin walking in front of the museum just then out of nowhere he sees the Neighbor peek through the window similar to the Neighbor's introduction in the beta.
EDIT: But also, every time we make progress like get keys for the locked museum rooms and stuff maybe the Neighbor can watch through us through one of the windows so it's more like he's been watching our progress and stuff, that would definitely add creepiness to the game.