.....at the Metropark, NJ train station you can catch Amtrak trains to Boston.... more information on schedule and prices is at amtrak.com..... you can type-in "Metropark, NJ" as a station name, along with Boston.
For Chicago..... the Amtrak train system also goes to Chicago......you w ould start at Metropark, NJ then connect to another train in New York City Penn Station or Washington, DC.....you can find the schedules and prices on amtrak.com
For train travel advice, please see the Amtrak section of FlyerTalk.
To make a time/cost comparison of train vs. flying, the costs for airlines and trains are lower when you make a reseravtion many weeks in adavance, and sometimes for middle-of-the-week days or Saturdays.
For example, looking at Southwest Airlines for Wed. Sept 12, a flight from Newark (EWR) to Chicago-Midway Airport (MDW) is $100 one-way.
Hope this is helpful.....