just to give an idea, Boston to Chicago would probably be near 16-20 hours straight drive. Assuming you go through Canada to do it(shortcut). but you could go to Niagara Falls/Buffalo on the way.

Philadelphia would be a good stop too. Lots of sightseeing there. (Liberty Bell, Declaration of Independence etc.) Get a traditional Philly CheeseSteak.

If you go through Ontario, Canada, you could visit Point Pelee, most southern point in Canada. There's a few catters' in this area, being Detroit/Windsor. Myself and ClintonHammond, ddw to name a few.

Hope that helps a little too.