Oh, here's something I was holding off on mentioning until I found the post that addresses it.
http://morganingram.com/wordpress/?p=951
This post specifically says that M called her mom to confirm that she was spending the night at a friend's house, and that as soon as her mom told her to sleep tight and she'd see her in the morning, a large rock or something struck the window and she expected shattered glass.
This makes me think that the stalker was angry to learn that M wouldn't be there to harass that night and possibly that M was the target instead of the parents?So much seems to have been aimed/revolving around M though that I don't really see it being the parents who were the targets, at least not initially.
Also, M's mom didn't know until a recent blog comment that the stables where their horses were boarded did the volunteer thing. She sounded pretty shocked to learn this, and shocked that the manager and her daughter never said anything to her despite knowing what was going on. Am I the only one who thinks this could possibly indicate that the manager knew or suspected that their stable/someone who worked there may have been involved somehow?