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I would highly recommend taking your nearest Metra line into downtown.  Some lines go to Union Station, which is only a couple blocks, a fast walk, to the Ogilvie Transportation Center.  Wisconsin people- Harvard, Antioch, or Kenosha are going to be your closest stops.
It appears you may be assuming that everyone’s familiar with the Chicago public transportation system when it’s possible that some people last used any form of transit 34 years ago in Des Moines, Iowa.[;)]  So is driving a reasonable option?

EDIT: Welcome, Jenn from New England.  Hopefully you’ll like it here in the Midwest.

Jenn is a born and bred native of the City of of Big Shoulders – accent and all!