On March 14th 2002, Brenda testified that all of her kid’s bedrooms were easily identifiable from the outside when the doors were closed:

Dusek: as you turn left to go to the kids’ bedrooms, which is the first one you come to?
Brenda Van Dam: Dylen’s.
Dusek: when his door is closed, is there anything on his door that would indicate anything at all about the type of person, male, female, sex, anything of the person —
Brenda Van Dam: he has tarzan on his door.
Dusek:what do you mean tarzan?
Brenda Van Dam: it’s like a 3-d sticker on his door.
Dusek: where on the door?
Brenda Van Dam: it’s down at his level. he put it on.
Dusek: how big is it?
Brenda Van Dam: it’s about this big.
the court: show me.
the witness: (witness indicating.)
Dusek: about a foot?
Brenda Van Dam: no, actually, it’s probably about — i’m not sure of the size. maybe six inches by six inches.
Dusek: what colors?
Brenda Van Dam: green and yellow and brown.
Dusek: kind of bright?
Brenda Van Dam: yes.
Dusek: the next bedroom that you would come to would be whose bedroom?
Brenda Van Dam: Danielle’s.
Dusek: does she have anything on her door —
Brenda Van Dam: she has.
Dusek: — that would indicate whether or not it was a male or female in that bedroom?
Brenda Van Dam: she has pink and purple hearts and flowers.
Dusek: about what size are they, ma’am?
Brenda Van Dam: they are, I think they could be a foot long altogether, and maybe five inches in height.
Dusek: how are they attached to the door?
Brenda Van Dam: they’re wallpaper from her border and i cut them out so that i could put them on the door. so they’re glued on.
Dusek: can you estimate how long they have been there? ballpark?
Brenda Van Dam: approximately two years.
Dusek: and as you continue down the hall, do you come to a third bedroom?
Brenda Van Dam: yes.
Dusek: who’s bedroom is that?
Brenda Van Dam: Derrick’s.
Dusek: does he have anything on the exterior of his door to give us a clue as to what type of person stays in there?
Brenda Van Dam: he had a pokemon sticker.
Dusek: what’s a pokemon?
Brenda Van Dam: they’re trading cards. it’s a game.
Dusek: how long had that been on?
Brenda Van Dam: about two years.
Dusek: where did that come from?
Brenda Van Dam: the trading card store.

According to Brenda Van Dam’s testimony it was easy for anyone to distinguish Danielle’s bedroom; if Westerfield had entered the house he had never been in before, all these stickers should have make it very easy for him to find Danielle’s bedroom without any hesitation

On March 11th 2002 Detective James Clifford Collins employed by San Diego Police for 30 years testified. His testimony doesn’t indicate that finding Danielles’s bedroom was as easy as described by Brenda Van Dam:

Feldman: sir, basically, I think you told us you were the law enforcement officer who was I guess assigned primary responsibility in the beginning to locate Danielle Van Vam; is that correct, sir?

Collins: not in the beginning.
Feldman: after some short period of time; is that correct?
Collins: at 10:30 in the evening.
Feldman: and that would be on which date?
Collins: February 2nd.
Feldman: and by then Danielle had been missing for how long?
Collins: she’d been discovered missing at shortly after nine o’clock saturday morning. so this was about 13-and-a-half hours after she was discovered missing.

[–]

Feldman: all right. did you have anything to do with the search of the Van Dam residence? or searches, I should say.
Collins: I was involved in one search of the Van Dam residence.
Feldman: which search was that, sir?
Collins: that was done about three o’clock, the morning of February the 3rd.
Feldman: and was one of your purposes in searching the Van Dam house to seek to locate, for instance, blood that might have been present at the scene?
Collins: no. my search was to do another search to make sure that Danielle was not anywhere in that house.
[–]

Feldman: have you seen a floor plan of the Van Dam residence?
Collins: I haven’t seen the floor plan but I’ve been in the house.
Feldman: do you remember that there’s a stairway?
Collins: yes.
Feldman: and when you get to the top of the stairway, do you remember that there’s several rooms?
Collins: yes.
Feldman: with regard to the rooms, when you first saw the several rooms, could you tell whose room was whose?
Collins: No.
Feldman: because there was nothing that plainly marked, for instance, that one room belonged to one of the Van Dam children, another room belonged to another of the Van Dam children; correct?
Collins: That’s correct.
Feldman: and there was nothing that plainly indicated, for instance, that which was the master bedroom as opposed to another bedroom which was down the hall; is that correct?
Collins: no, I assume the master bedroom was the one that was away from the other three bedrooms.
Feldman: regardless, though, were you shown which of the bedrooms in the upstairs area was Danielle Van Dam’s?
Collins: yes, I was.
Feldman: by whom were you shown that?
Collins: I don’t recall.
Feldman: you don’t recall whether it’s the Van Dams or one of the officers that was working with you, sir?
Collins: it was not the Van Dams.
Feldman: did you enter the room that was identified to you as Danielle Van Dam’s?
Collins: yes, I did.

The above testimony proves that on February 2nd, Detective Collins is unable to tell whose room was who’s because “there was nothing that plainly marked that one room belonged to one of the Van Dam children, another room belonged to another of the Van Dam children.”
Detective Collins didn’t see any of the stickers that Brenda Van Dam pretends were on the children’s bedrooms doors for two years.
If on February 2nd, Detective Collins didn’t see any of the stickers while he was in the Van Dam’s house which was well lit, how could David Westerfield find which room was Danielle’s if he was in the Van Dam’s house AT NIGHT without any light on?