The Superliner Roomette is not huge. At three and a half feet wide by six and a half feet long, it's less of a bedroom and more of a well appointed closet. But it's your closet, all yours, with a door that closes and locks you away into blissful privacy. And privacy is very nice when you're trying to make progress on your manuscript.
A folding tray table attached to the wall between the two seats makes a serviceable desk--one that is not attached to the back of a seat in which a small child is bouncing around or raising and lowering the leg rest, it's worth pointing out. The room's single outlet keeps your laptop going long past its battery lifespan. Bottled water, juice, and coffee coffee coffee is freely available for self-service in your car. And the huge picture window provides endless inspiration as you watch the country roll by.
Meals come free with your sleeper accommodations (alcohol and gratuity not included). Generally these are served in the diner car by reservation for dinner and by first-come-first-served for breakfast and lunch. You are not required to dress up in this casual day and age, but you may be required to socialize; seating is community-style. For the most part you're to leave personal belongings in your room rather than bring them to the diner, space being at a premium, but a small notebook for jotting down ideas is unlikely to offend.
If you're on a roll and would rather write through dinner, or if you're just feeling introverted, you may ask your sleeper car attendant to bring you your meal in your room.
When you're ready to go from vertical to horizontal, your sleeper car attendant will convert your sitting room into a bedroom. The two chairs slide together to convert into your bed; if you're traveling with a companion, one of you will take the upper bunk that folds down from the wall. That notebook for ideas-jotting can easily slip under your pillow, on the floor or the shelf beside the bottom bunk, or in one of a couple of safe-keeping spaces in the upper bunk.
Please do not attempt to make up your own bed. It makes the sleeper car attendant nervous. It also might injure you. Your sleeper car attendant has experience with handling the various moving parts on a speeding train; you don't. Be safe and let your attendant do for you those things that your attendant is there to do for you.
For a closer look at your accommodations, use the media links at the bottom of the Superliner Roomette description page.