Well for your first segment (which I assume would be on the Lake Shore Limited) I can’t say much. I’ll start at Chicago.
Since you are in a roomette on the Southwest Chief (SWC) you have access to the Metropolitan Lounge in Chicago. They have free snacks and drinks and plenty of comfortable seating. Just follow signs to it.
The Southwest Chief is a bi-level train, meaning there are two stories. Depending on your room number (1-10 upper, 11-14 lower) is which level you are on. There are bathrooms on both floors however you can only pass between cars on the upper level.
The Lake Shore Limited is a single level train by the way.
A roomette is a great room in my opinion, but it is a little small. There is a luggage storage area on the lower level. I would recommend bringing 1 or 2 bags up to your room and leaving the rest down in the luggage area. Roomettes can also get hot. I would recommend bringing a miniature fan. The Roomette has only one outlet, so if you need to charge several devices, I would recommend bringing a power strip.
Amtrak is nothing like airline travel in regards to baggage. You can carry on up to 4 bags per person. However, if you can carry all your bags, they generally don’t mind more. (I carried 6 small bags on a LD train once, no one said anything). You can also check bags. Cleveland, Chicago, and Flagstaff are all stops that allow checked baggage. You can check up to 2 bags per person for free. If you need any assistance with your bags getting on/off the train, I can speak that Chicago and Flagstaff both have the means, I’m not sure about Cleveland however.
The Southwest Chief has a full service dining car and observation car. Both are a great place to spend time in a social atmosphere and watch the country go by.
Besides that, scenery wise, most people think that the part of the route through New Mexico is the prettiest. However, if I were you I would be up in the morning through Western Kansas and Eastern Colorado, where I have never seen a sunrise that wasn’t beautiful.
Feel free to ask any more questions!
-Peter