The difference between settlement types is largely physical, determined by population size, defenses, and the availability of resources. Magnitude affects everything, including the amount of territory covered to how much of it can be farmed or protected and how often the settlement is visited. Those with a lot of traffic, something to offer residents, or both, are likely expanding. Conversely, those with less to offer may be shrinking. Most of this chapter will apply equally to all settlement types, but here we’ll look at specific considerations.
These are structures or groups of them where the population is too small (or not perpetually present) to qualify as a village. Whether we call them outposts or something else, the smallest permanent dwellings are anything from a single building that might not be perpetually manned, like a tower, up to a larger fort more like a castle. An outpost might only be needed during certain seasons or conditions, getting overgrown during the absence of people, or just minimally staffed. It could be a refueling station or scientific observation post, particularly in SF.
This has practical consequences. Farming is unlikely if no one is there year-round, requiring residents to either bring food with them, hunt for it, or be supplied from elsewhere, which is believable if the outpost is associated with a larger settlement that built or maintains it. We take for granted food and water supply or the presence of doctors/healers, repairmen (such as blacksmiths or mechanics), or police, but many of these may be missing from the outpost’s staff. Decide which absences make sense or propel your story forward; wounded characters with no healers around adds tension, but a missing blacksmith is harder to make interesting or worth commenting on; in SF, those who can repair equipment are seemingly needed more often.
While it’s typically known who built a larger settlement, an outpost might have been long abandoned and possibly used by someone other than its builder. This can offer mystery, such as hidden rooms or ones with disturbing contents and purposes. There’s also the possibility that whoever (or whatever) normally occupies it will return and catch our characters making themselves at home. It’s important to decide who, if anyone, has been using this place lately, its condition, and what we intend to happen to our characters while here. Do they know about this place and think it’s abandoned, or do they know something bad is here but they need it for shelter anyway and come prepared for battle? Unknown outposts that are stumbled upon are the most nerve-racking if something seems “off” about the place, as though danger lurks.
Our less civilized species are likely unable to create buildings. This suggests they’re the ones to take over somewhere abandoned or often unoccupied. They may even do so seasonally so that the regular inhabitants know this and prepare, either by laying traps, making it otherwise less desirable when gone, or coming back heavily armed for the yearly reclaiming of their outpost. The unsavory inhabitants might also leave behind a mess, including carcasses of food, enemies, or both.