I'm a suburban denizen, but a good bit of my work takes place in the heart of Chicago. When I first moved here, I was doing a lot of driving, but I eventually migrated to more public transit usage.
There is a Pace bus line that has a stop just a short walk from my home. It drops you off at Rosemont, where you can go inside, head up the escalator after an optional Dunkin stop, and catch the train. However, the bus tracking is not the most reliable service out there. With a schedule that keeps you guessing and doesn't always have super frequent buses, it delays the journey a good bit.
First things first, before we get to Cumberland: what train? I'm speaking of the Blue Line. It runs from O'Hare to Forest Park, though sometimes it ends at UIC Halsted. This distinction doesn't matter for my commute, since I get off smack dab in the center of it all in Chicago. The Blue Line isn't exactly luxury travel: the seats are hard, it gets extremely crowded during peak times, and the ride is not the smoothest; as you get out towards the suburbs, the train usually goes way too fast, careening down the tracks and making passengers whack their knees on the seats in front of them. That said, it's a convenient way to get into the city, so I live with it.
I bought a new car recently, so I'm a bit less hesitant about getting out on the road (my old one wasn't safe to drive at the end of my ownership). Therefore, driving to Cumberland and catching the Blue Line from there has become my new preferred commuting strategy. Let me show you the ropes, at least for those approaching from the west.
I take I90 from home and, after a few miles of reliably smooth sailing, I hit the 294 interchange. If you're not getting on 294, I suggest getting in a lane towards the left; this will help you avoid some of the traffic getting to 294 South/190 west. Furthermore, there's an exit right afterwards that takes you to 294 North, and a lot of people like to sidle up next to it so they can stick their metal nose in and cut in front in line. All of this clogs up the artery like infrastructural McDonald's.
Keep going past Cumberland South, and get off at 79B (Cumberland North). It's a kind of strange area of the highway; I try to get in the exit lane on the late side, because there's some merging that throws me off easily. My strategy is to stay one lane left of the line when it turns solid and merging begins. Then, I gently go rightwards after merging is complete. Once you're off, though, center yourself and head towards the traffic light. You'll want to be in the middle lane, which goes straight. Then, head right in. Once you've crossed into the Cumberland complex, stay towards the right (left is for buses). You'll see signs for parking, which you'll want to follow to the garage. Pick a lane, grab a ticket, and drive on in.
This is where it gets a little confusing, because the layout isn't exactly intuitive. As soon as you've taken a ticket, you'll see a small concrete island. I have yet to get any clarity on exactly why it's there, but the strategy that has yet to fail me is hugging the left side and proceeding into the first row of parking. This is primarily comprised of ZipCar spots and accessible parking. As such, I've never parked here, but if you have a tag to use accessible spots, I don't think I've ever seen there not be at least one available, though I'm not sure about if they have those double-wide ones to accommodate vans with ramps.
I travel during peak hours: weekdays, arriving at the parking garage between 7:30 and 8:00 AM. As one would expect, the spots are mostly taken by then. That said, I have always been able to find myself a spot. Turn right after you get through the first row, and from there, you can turn right into one of the other rows to check for parking. Because of the way the traffic pattern is laid out, always start from the back row. This is because once you have checked through a row, there is no way to continue "upwards" away from the station to try the next row; it's one-way. So you can go to the very back, check that row, and then turn right if needed to go to the next (middle) row.
I always pay the tickets by credit card, and at time of writing, parking for a full day in the office is $7 U.S. I am not sure if they accept cash at pay stations, but if you're paying with a physical credit card, then keeping the ticket in your car and paying at the exit is no problem. You'll simply scan the ticket under the machine, and once prompted, insert your card. Once you've taken care of payment, you can discard your ticket in the mini upside-down cone below the machine. I am afraid I do not recall if these machines offer receipts, so if you need one, it's worth checking what options you have.
Once you've parked, you should have three options for getting to the platform: elevator, escalator, or stairs. The escalators are extremely narrow, so if you're in a hurry and get the misfortune to be stuck behind someone, they're likely not your best bet. Once you're upstairs, follow the signs for the tracks. You'll pass through a corridor to the right, where you'll generally find some Jehovah's Witnesses that you can ignore, and then turn right again towards the turnstiles. By this point in my walk, I will have pulled up my Ventra app to purchase a day pass, so I'll be ready to roll: I just present my phone at the reader, and I'm in.