Need Chicago help

Ooops, double post.

I think there is still an RV park in Elgin and Sycamore - towns way west out to near where my wife and I grew up. I spent 4 1/2 years living in Chicago going to engineering school. It could be pretty rough then - only got robbed few times - but we would never go back into the city proper again now. McCormick Place is south which is not the direction you want to spend time in the city.

the buses are excellent. Use google maps to help you. The Driehaus museum is walkable from The John Hancock stop, and should be a pleasant walk. BTW consider eating lunch at the restaurant that is just one floor below the top of the Hancock building - get a great, uncrowded view of the place, for about the same price you would take to go to the top. Or just get a drink.

The Cultural Center near the Millennium Gate (Jelly Bean) is also a must see. I would go to that over the Clarke and Glessner houses if you have limited time.

To your first question, there is a walkway that goes under Lake Shore Drive and over the tracks, which connects Soldier Field to the area by the Gessner House. It's shown in the center of this map:

https://www.google.com/maps/place/1800+S+Prairie+Ave,+Chicago,+IL+60616/@41.8581774,-87.6178819,260m/data=!3m1!1e3!4m5!3m4!1s0x880e2c80ffa77e07:0x5f05cb7144494aa0!8m2!3d41.8577331!4d-87.620988

As to the Driehaus, it is about 7 blocks from the John Hancock, so that is definitely walkable.

These are not bad areas, although I'd at least be on my toes across the tracks from Soldier Field. But they are not the "bad part of town".

As to FHU CGs:

There is train service across NW Indiana to one of the downtown stations. It's possible there is a campground somewhere out there that would not be far from one of the train stations. If you can get a ride to the local station, from there you can get into the city. Check the schedules as they don't run a ton of them. It's called the South Shore Line. You might start a separate thread asking about CGs near the South Shore Line.

I don't know where you board the Big Bus. Uber is very widespread and affordable in Chicago.

There is a Harrah's casino in downtown Joliet that I know has some RV parking. It's an urban setting, including the lot where the RVs are parked. There is security, though. There is a Metra train station a few blocks away, where you can take the train to Union station in Chicago. I would suggest doing any walking around in daylight there (in Joliet). Downtown is busy during the day but night is spooky, and it directly borders on bad neighborhoods. There might be Uber there, I don't know. There are taxis.

Outside of Joliet, sitting by itself, is the Hollywood Casino. They have an actual RV park. You'd need to get transport to/from the train station.
http://www.rvparkreviews.com/regions/illinois/joliet/hollywood-casino-hotel-rv-resort

There is also a casino in downtown Aurora. Aurora is served by a Metra train as well. The station is called the Aurora Transportation Center. It's across the river from the casino, roughly. Don't know if they have RV parking at the casino, but it is a big complex. It's also an urban setting but a little softer looking than Joliet. At night I'm sure it's the same as Joliet in that it's vacant except for the casino traffic.

I am also not from Chicago, but have been there a few times, if it were me I would probably try to stay a ways out of town but near a metra line station well out of Chicago and ride the train in. In my limited experience with Chicago pubic transit the Metra trains seem a lot nicer and safer feeling than the subway lines and buses. This way you can mostly avoid the 10-15 lane wide sections of freeway that feeds into downtown.

There is Illinois Beach State park in Zion IL. probably the closest thing to a campground for Chicago. I believe you can catch the Metra train down to Union station which is just about across the street from the Sears Tower (I refuse to call it Willis Tower)! the Marshalling Yard is behind Mc Cormick place. it has security and is pretty safe!

As a Illinoisan that's all I can say. I avoid Chicago like the plague. I live in the NW suburbs, but grew up in the city and adjoining suburbs. I even have my routes around the city when I leave south!

Have a good trip!

First of all I am not a fan of Chicago and avoid it like the plague, so I am not the best one to answer your questions. In terms of RV parks there are no good options in Illinois. There is a KOA near the town of Union to the northwest. It's pretty far out though. Some people have stayed in Indiana, so you might want to look there.
Here's a link for some reviews on the McCormick Place Marshalling Yard. I would advise using public transportation instead of driving. I'm not sure what you're driving, but pickup trucks aren't allowed on any boulevard or Lake Shore Drive. In addition are some bridges that are pretty low. Don't trust clearance signs. Expect traffic to be bad most of the time.
The public transportation system is set up as follows: Metra is the suburban train system. PACE is the suburban bus system. Transportation in Chicago is run by the CTA. Assuming you have a smartphone you can pay fares for all three with an app called Ventra. You can use the public transportation feature of Google Maps to plan your routes.
As far as safety goes downtown Chicago is pretty good. Try not to look like a lost tourist. Walk with a purpose and be aware of your surroundings. Crime can happen anywhere but is more common on the west and south sides. Gangs are a huge problem and shootings are pretty much a daily event, worse on the weekends. There have also been shootings on the expressways, again west and south sides.
Again, I am not a fan and there are other plenty of people who will say how wonderful Chicago is. I hope you find this helpful and have a fun and safe trip.

One travelog video I was watching claimed McCormick Place sells overnight RV parking in their marshalling yard (where truck and rail cargo is loaded and unloaded)... you prepay and get a reservation ticket from a website?

McCormick is a bit south from the Mag Mile, etc but it is A LOT closer than a KOA or something like that - only a few blocks to public transit (bus, l-train, etc) and then the city is yours.

It's just a secure parking space, not a FHU rv resort. Bring your own power and water, let the City do the cooking.

Regarding your other stops, there's a bus stop at every other block as I recall up and down both sides of Michigan Ave, as well as LaSalle I think? Sorry, it's been years since I was there last. I'm sure you can find a stop closer than Big John to the Driehaus.

Google shows a bus route stopping right near Erie, and the red line stopping 3 blocks north or 3 south of Erie.