Kingbri1,
Since you are booking sleepers for the Empire Builder, when you get to Chicago make sure that you take full advantage of Chicago's Metropolitan Lounge. These lounges are a nice quiet refuge in the often-bustling train station. They have nice plush chairs, conference rooms, computer terminals, newspapers, TV's, luggage storage, free soft drinks, juices, coffee, tea, and clean safe bathrooms. They also allow you to board your train before the rest of the masses.
It is located on the lower level of Union Station, which is also the track level. If you are standing in front of the Amtrak ticket windows, then the Amtrak waiting area is to your left. When you enter the main Amtrak waiting area through a sliding glass door, just walk forward and slightly to the left. There should be another sliding glass door along with a sign, unless they've changed the entrance in the last few months. Again, just show your tickets and relax.
They'll also give you a card that contains the time that you need to return to the lounge by, in order to board the train and not miss it. If you do leave the lounge, take this card with you as it is also your pass for reentering the lounge. Just wave it at the attendants as you walk in and one will usually look up and acknowledge you and the card. Note the Chicago lounge can be very busy and it sometimes can be hard to get a seat, but you still get the free stuff and priority boarding.
Note: They may make you leave your carry-on bags in the luggage room inside the lounge, if the lounge is very crowded. There is a redcap manning this room who will give you a claim check for your bags, such that you can claim them shortly before you board the train. One nice advantage of this is the fact that you can park your carryon bags here, while you wander around Chicago and do lunch, assuming that your trains arrive on time.