In the early classroom scene with Mr. Rooney, the word "tomorrow" is misspelled as "tommorrow" in "Tomorrow's Assignment" on the chalkboard. It's doubtful that an arrogant English teacher would misspell this word.
When Steve finds and bonds with the janitor in the basement boiler room, Steve asks, "What the hell is going on around here?". In the janitor's explanation, he describes a fatal car crash. He says that 4 teenagers "got properly squiffed on Daddy's gin", but then moments later, while describing the crash, says that beer cans covered the road "as far as the eye could see".
It's perceivable that the family is re-locating from Seattle to Cradle Bay Crescent Island via ferry. Chicago, however, is the only town of origin ever mentioned. Crescent Island, incidentally is an artificially created island, for National Wildlife Refuge purposes only.