Somewhat enclosed space with a donation box. Water, mosquito net or walls, air conditioner (with off timer) if completely enclosed.
In more natural places, a gazebo with an outdoor bathroom. Perhaps a public bookcase, for sharing experience and knowledge to others.
In less natural places, any enclosed space. Korean spas (jimjibang) are exemplary. Loft-like space with hardwood floors, shared bathrooms, lockers, [re-usable? / easy to wash] pillows and matts. Perhaps that example is too large. Shrink that example, and it still works. A room with hardwood floor (with pillow and mats), locker, shower room.
Isn’t this what capsule hostels do?
This idea is good for traveling to remote parts (hiking paths, paths to remote villages), or when traveling alone, or when traveling with a group of friends.
This idea is bad for those expecting an organization, a space with a vibe set by the owners, with a certain class of people to socialize with.