In the meantime, we wanted to offer some additional Chicago transportation insight...
Conveniently, every paved method of ingress to the city from the 'burbs is under-construction. Please build in some extra travel time if you are planning to come into the city via automobile.
While we certainly do not highly condone vehicular travel from the suburbs, we understand it is unavoidable in some cases. Please see below for a host of parking options very near The Rookery. We recommend the Sears Tower garage at West Adams & South Wells (shown in pink on the map).
But, why trifle with road rage at all? Trains are a far more sophisticated form of travel and both the suburban Metra system and the city's elevated "El" train have stations a hope, skip and a jump away from the The Rookery. You can check Metra's suburban train schedules here and the El train schedule here (FYI, Quincy or Washington Street stations on the Purple line are your best bet).