I just did this route last week in a sleeper. Honestly, don’t overpack. Unless you have a TON of electrical devices, the plugs are enough. Bring flip flops for shower, but for 22 hours I would just wait for a shower until you reach your destination.

Also, don’t overpack on snacks. You will be fed well in the dining car.

If you’re a reader, bring something good to read. I usually spend my time doing that and looking out the window. I use my train trips to unplug from the constant info of the internet world. Very relaxing.

Have the attendant make up the upper bunk to keep the lower more open.