I certainly agree with what you said. I believe that the fact we see her room somewhere where it shouldn't be indicates that she already is inside her Abyss. But she might be quicker than James. The newspaper has "today's date" on it and a trip to Silent Hill by foot (I can't imagine how else she could arrive there) can;t be a short one.

Well obviously she hasn't been there for days or anything. The process of the journey seems to be steady enough as to last a day or so to reach it's ultimate conclusion. She probably killed her father last night and ran away under cover of darkness, then showed up at say...6:00 AM, to be generous. The newspaper doesn't have to be real in that Angela saw it; it could just be an article created to express her crime to James (or even herself, which James found after). Going from that, let's say James met her at...I would say 10 AM. Four hours is enough to get you into the Abyss, I'd think.

If he didn't get to her, then that part wouldn't have been in the game. The player would have no clue since they see everything through James' eyes and mind.