My bad. I realised I'd misread your friend as being her friend, telling you to lay off.

If a guy I hardly knew drove an hour for me, I'd be a little put off. I'd much prefer the "I was the in the area and decided to drop by" line. It's just a little too much commitment for not even the start of a relationship if you know what I mean. But I dunno, I can't speak for all girls.

That aside, I agree with other posters that she's being inconsistent with her actions. It's pretty fickle of her to encourage you at one moment, and then suddenly cut off all contact with no explanation. She could be dealing with personal issues, but that wouldn't explain why her friend couldn't just tell you that she's going through a tough time. It sounds like her friend knows something, but it's not her place to say. The most probable explanation to me is that she really is that fickle at 19, and just lost interest. Sorry to sound harsh, but if she liked you enough, she would have at least replied by now?