You're overthinking it. Sleep in regular pajamas, keep a pair of shoes next to your bed, and pack a change of clothes in your go bag. If you're not one of a hundred people wandering around in their sleepware, you can use a neighbour's house to get dressed. If you are, just duck behind a car. Modesty standards are probably going to be a bit relaxed.
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Hope for the best and prepare for the worst.

The object in life is not to be on the side of the majority, but to escape finding oneself in the ranks of the insane