Just some ideas that my be so obvious as not worth mentioning:

1. Extra cash, small bills in several places.
2. Your cell phone and hers, both fully charged.
3. A couple of cheap disposable dollar store ponchos even if there is no chance of rain.
Not quite on topic but also:
4. A small notebook--keep track of the names of the people DD interviews with (if possible, get a business card). Immediately after returning home, have her write and snail mail a short note thanking them for their time and expressing her desire for admission.