I've mentioned somewhere (I think) that I went on a three day solo train trip. That train trip was on the California Zephyr route that starts from Emeryville, California and ends at Chicago, Illinois, crossing in a sorta straight path across the middle of the U.S. from the west to the east. I took it all the way (three days!), and it was amazing. I briefly considered settling with just coach seats, but look, I am not a spry young adult anymore, so I splurged on the cheapest private room for myself. The room comes with breakfast, lunch, and dinner, and they are all substantial meals with unlimited non-alcoholic beverages (and one alcoholic beverage per dinner). The sleeper rooms are also in separate carriages that have their own toilets and a bathroom. Totally didn't regret it.
That's my tiny room! And my feet and bags.
( The rest of the photos and my experience under the cut (image heavy) )All in all, 100% would recommend anyone who has the time and the money to spare to do this trip! This leg of the trip cost me around USD1400 (I added another train ticket to my next destination from Chicago, so I paid a little bit more than that).
Do it while you still can! (Amtrak had a reduction in force on the second day of my trip... so this is half "haha, just joking" but also half not)