My daughter is a Freshman at an out-of-state school. One of the things we felt strongly about was her access to us (bus or plane), so a campus where she was in the middle of nowhere and unable to get home fairly quickly (or vice-versa) was not really an option. That might give her mother some peace of mind. Maybe they can do some research and determine a time limit (for example, XX hours away by bus or plane) that they are both comfortable with.
I completely understand her fear for her daughter, but at some point, her daughter needs to be on her own for her own growth and happiness. When she gets to school, she should immediately talk to her advisor as well as campus police about her potential situation. Most campuses are quite adept with security measures and they are required to maintain privacy for her.
Best of luck!