Is this a craigslist scam?

The thing about doing any kind of business over the internet is that you have to just do what you are comfortable with. This is true of any kind of face to face transaction. If you think it is sketchy then you have to decide if its worth it. She is sending you laptops though and not the other way around. If she will not do business over the phone and you insist on it then the deal just might be possible. Politely ask her to call and if she does not want to you can politely decline.