I would imagine that a school would have available outlets to plug into during the day. Even on a 120V she would have more than enough for the trip, if she can plug in at work that is. Plugging in after work most likely isn't going to be an enjoyable experience with the vehicle, even with busy work.
I second the idea of contacting the school about installing a 220V as well, in my area the majority of my customers have been met with excitement when bringing up the idea to there work places. If you are able to arrange that, even if you take on some of the cost, you should come out ahead and be able to enjoy a FFE!!
Havill-Spoerl Ford Lincoln
Fort Atkinson, WI