You could put it on a Form 4852, which will probably result in more tax than on a Schedule C.  Or help her file an SS-8, which might stir up enough trouble that she'll be blacklisted for life.  You know how zoos can be.  What you haven't told us is why you think she has a tax home.  Is her school in the same town as her family's home?  Did she have duplicate living expenses while on this assignment?  Think of the turtles at the zoo.  They can't be away from home because they carry theirs around with them.