Another alternate airport, closer than EWR - would be to consider flying into SWF in Newburgh, NY on the Hudson (Stewart Airport). A quick glance showing flight options from/to ORD with connections but no "non-stop" - car rentals from Hertz or Budget, and it's about a 3 hour direct going across to Ithaca on I-84 & Rt. 17 via Triple Cities/Binghamton, etc.

Check the airfares & schedule, etc. to see whether that's competitive along with the convenience factors vs. flying into EWR with more flight options - and a longer drive of about 4.5 hours depending on urban traffic in NJ - just a small one-way toll at the Delaware Water Gap.