I recently showed this game to my nine-year-old son. He had a lot of fun with it, spending a couple of hours playing it over a few nights. He even went so far as to ask me to print out some maps of the U.S. so that he could practice finding routes from state to state.
Overall, my son really enjoyed the game, and it increased his knowledge of U.S. geography. A win.
I wouldn't really call this "interactive fiction," although it is parser-based. It's more of a text-based mini-game. Thus I don't feel I should give it a star rating.