IN summary(If I am understanding correctly) she can have either of the following problems:
1.) The tracks are not fully connected, and she needs to find a buffer.
2.) The destination for the good does not accept that particular good(I.E. sending passengers and food to a village).
On a sidenote, where did her map come from? Not only can you see the state lines, but the map apparently extends from just north of the Canada border to deep into Mexico.