Bunkhouses. They’re not just for the wild west anymore.
Traditionally, they’re a rustic barracks-like building used to house itinerant cowpokes, who were mostly single young men. Or in these here parts, a bunkhouse might have been where lumberjacks slept in a logging camp.
Now, although as far as I know the term doesn’t have an official real estate definition, it’s used to refer to an accessory building that’s something less than a “guest cabin.” A bunkhouse doesn’t have a kitchen, and may not even have a bathroom. It’s just for sleeping. (In practice, it might also be used for late-night poker parties, a place for surly teenage grandkids to hang out on rainy days, etc. That sort of thing.)
Some, although a bit on the rustic side, are actually not too bad. Here’s an example from northwest Wisconsin. It’s in Solon Springs on the east side of Lake Saint Croix. For a peek inside, just scroll on down.