Ha. Could basically be anything. Snow would be weird, but it’s happened. 90 would be weird, but it’s happened. Most likely upper 50s / light jacket weather.
I’ve done a long distance train trip once about 20 years ago, from San Diego to eastern Washington, but that was 4 trains and two buses, plus it was coach so I had to try to sleep in a chair surrounded by strangers. This’ll be a straight shot end-to-end on the Empire Builder in an Amtrak Roomette, which is still small, but I’ll have a private place to lie down, and it’s something I’ve been wanting to do since that first trip.
My previous trip was in the days before smartphones, so there was definitely a lot of staring out the window for hours at a time. I don’t believe the EB has wifi, and a good stretch of the run is through the vast open part of the country where nobody lives, so I expect there’ll be much of the same. I’ll probably bring some books or load some stuff onto my tablet to watch along the way, and I’ve been advised to bring a power strip with me since the cabins predate the widespread adoption of personal electronics and only have one outlet.
Giardiniera is another thing to try, if you like that kind of thing. Available elsewhere in the US but damn near ubiquitous in Chicago.
I’m familiar with giardiniera. I’ve ordered Marconi’s hot giardiniera off Amazon a few times when making crockpot Italian beef and it’s good stuff if a little too oily. I sometimes make my own by chopping up a jar of Mezzetta giardiniera and adding hot peppers to it.
As far as pizza and beef goes try the Chicago-est Collab. It’s a Lou Malnati’s pizza with Portillos beef and green pepper.
Just ate one last week, delish!
One thing to keep in mind with the CityPass is that you may still need to make reservations for some attractions, like the boat tour or the Sears/Hancock towers. And some places have a separate line for CityPass, so you can get in faster. (Sort of like TSA Pre Check.)
On our boat tour, the guide said that general consensus was that the Sears Tower was better during the day, and Hancock was better at night.
I’d recommend against Pequod’s for a visitor with time for only one pizza. It’s ok, kind of bready and under-topped IMO, and not the characteristic cheese-pulling dee pdish delight that people are picturing or what Jon Stewart was sneering about. I’m extremely partial to Italian sausage.
Be advised that Kuma’s is a rock bar and extremely loud, potentially to the level of discomfort.
Don’t disagree with either comment.
I once stood ten feet away from the stage at a Motorhead concert. Sounds like my kinda place.
As did I! That was you next to me? 
(And, that is why I have partial hearing loss.)
Yeah, Pequod’s is kind of its own thing – along with Burt’s Place, which was started by the same dude (Burt Katz, RIP.) It is absolutely fantastic deep dish and my favorite in the city (well, Burt’s when Burt was around in Morton Grove was my favorite), but it is not typical Chicago deep dish. It’s kind of a cross between Chicago deep dish and Detroit-style pizza: it’s a bit more doughy, and has those caramelized (some would call “burnt”) edges. For bog standard yardstick-calibrating Chicago deep dish, I would go with Lou Malnati’s. For stuffed (which is either its own category or a subset of deep dish, depending on your pizza taxonomy), I’d head over to Nancy’s, but Giordano’s is everywhere and people seem to like it (I don’t. That is to say, it’s still reasonable, but if I’m in the mood for stuffed, I’m getting it from another place.)
To the OP:
I heartily endorse all of Snarky_Kong’s comments. If you go to Al’s, I suggest you go to the original on Taylor Street. The franchise locations are just not the same. Be aware that Al’s is sui generis among Italian beefs. Their spicing is very different than any other place. There is cinnamon, allspice, and other Middle Eastern/South Asian type flavors going on there in addition to the typical Italian spices. It can be polarizing. It’s also pricey for the portion size, IMHO. That said, when I’m in the mood for Al’s, nothing else will do, though Johnnie’s in Elmwood Park and Chickie’s in Hillside (formerly down the street from me) are my favorite beefs. But they are a bit of a trek and there’s no reason you’d wind your way up there. In the Loop itself, Luke’s does a very reasonable beef.
I ask for my beefs “dipped, hot and sweet.” That means they are briefly dipped in the jus, served with roasted sweet peppers and giardiniera. And, yes, giardiniera is oily, as you noted. That spicy oil is part of the charm and what defines it as a Chicago-style giardiniera as opposed to that Mezzeta stuff. It’s not supposed to be pure pickled vegetables – it’s a mix of oil and vinegar. It’s kind of like on an Italian hoagie, you want it finished with oil and vinegar, not just straight-up vinegar. Chicago-style giardiniera fulfills this role. You will also find that all the Subways in the area will have giardiniera available. (Not that you want to go to a Subway in Chicago. If you’re in the mood for an Italian sub in the Loop, go to Fontano’s Subs. If you want a truly great sub, go to J.P. Graziano’s in Fulton Market, just west of the Loop. I would rank it best in the city.)
A Maxwell Street Polish from either Jim’s Original or Express Grill would also be worth a try. Jim’s is the hometown favorite, but I actually prefer Express’s Polish next door. And if you order the pork chop sandwich beware, as it is served bone-in. The Maxwell Street Polish is a big fat Polish sausage that is grilled and served with copious amounts of griddled onions and mustard. Ask for peppers and you’ll get a big pickled pepper along with it (I think it’s a serrano – most hot dog places will give you what we call “sport peppers” down here, but this is much bigger than a normal sport pepper, and has more of a kick, as well.)
Hey, if you’re in town and I’m not doing anything, I’m willing to take you on a quick jaunt about town. I have most weekday mornings to early afternoons free, so drop me a PM if you feel like it.
I was considering making a stopover on an empty stomach and trying one from each. I’ve read about their long rivalry on Wikipedia and I want to judge for myself if there’s much difference between the two of them.
Honestly, there’s not. You’ll get a great Polish from either. While I like the Polish from Express better, I like the fries from Jim’s better. But neither are exemplars of great fries. Either Polish is a great yardstick for the style. Personally, I wouldn’t waste two food trips in a tight schedule on that. I would go for Jim’s (even though Express is my personal favorite).
I’ve been to Chicago a;few times. It might be my favourite American city. Obviously, the Straight Dope was/is centred there and locals know vastly more about it than I do.
I ended up eating more hot dogs than pizza, and more Italian beef than hot dogs. I had some good barbecue and seafood too. One place made homemade root beer. The Art Institute is great. I particularly enjoyed some nice Giaccometti sculptures and Magrittes.
Second City, Blue Man Group or shows might make a nice night out. I’d also check out if any concerts are going on when you’re in town. I’ve seen the Cubs and Blackhawks, but not the Bulls or Bears. I didn’t do Sears Tower, but went to some mediocre bar with a view.
It’s easy to get around on the overhead train. People are nice for a big city, the North US is a lot like Southern Canada.
Who said anything about two trips? I was thinking of getting one, plopping down on the sidewalk and eating it, then going next door and getting another. 
That might end up being my breakfast one morning.
Not much of a sports fan, but I see the Cubs are hosting the Padres while I’m there, so as a native San Diegan I might try to squeeze a game in. I also saw that Second City is doing an improv revue, so that’s also a maybe.
Are any of the gangster tours worthwhile?
So far, my agenda looks something like this;
Sunday: Arrive (hopefully on time), check in, pick up snacks and beverages from a nearby convenience store or grocery store, dinner from Giordano’s, John Hancock (if there’s time)
Monday: “Breakfast” at Jim’s Original, Art Institute, lunch at Luke’s, Sears Tower, dinner somewhere (Kuma’s?)
Tuesday: Breakfast somewhere, Museum of Science and Industry, lunch somewhere (hot dog?), boat tour?, dinner somewhere (maybe pick up a Lou Malnati’s if I want more pizza), Second City revue
Wednesday: Breakfast somewhere, Field Museum, lunch (Al’s Beef on Taylor?), Adler Planetarium, maybe Cubs vs. Padres (if it’s a night game), dinner
Thursday: Breakfast and then fly home
I can probably squeeze the boat tour in on Tuesday depending on what times are available.
There’s lots of talk about Chicago’s pizza and street food, but I haven’t heard of them having any iconic breakfast places. Is there some iconic diner somewhere that serves amazing pancakes or chicken-fried steak or biscuits & gravy or something of that nature? How about a good Italian restaurant that goes beyond pizza and subs, where I can get a knockout lasagna for dinner?
I see that there are plenty of 7-Elevens and Circle K’s in the Loop, and a Target grocery store, which I’m sure I would be able to get some snacks from for munching on in my room between meals. What are the alcohol laws like? I know most of the rules in Illinois are set at the city level and there’s no state-mandated cutoff time like most states have. Can I buy a six-pack or a bottle of liquor at a convenience store, or would I have to go to a grocery store for one or both? (Around here, convenience stores can sell beer or wine, but hard stuff can only be sold in stores with at least 10,000 square feet of sales floor space, because about ten years ago we decided to let Costco write our liquor laws for us.)
Does your hotel have a bar? Also, maybe pack booze for your trip. Booze can be expensive downtown.
I’m not sure. I’m staying at the La Quinta on Franklin - not the classiest joint, but it has good reviews, it was affordable, and the rooms have mini-fridges and microwaves which’ll be nice for that leftover pizza.
I’ll definitely be packing some for the train, but considering my state’s 20.5% sales tax on liquor, it’d have to be pretty dang pricey in the Loop for it to be cheaper to bring my own.
Jazz Showcase (nowadays located in South Loop).