I suppose this is going to be more of a general world building and my own personal rumination post. My goal is to look at the manga/anime Goblin Slayer and try to work out a semi-"realistic" way for the world to work as presented. And up front I want to admit that Goblin Slayer, like most fictional worlds, is more focused on presenting a general "image" and once you peer past the hood things quickly become a mess of contradictory assumptions the author wove to create the setting they wanted.
I fully agree with Bear Ribs take that the more probable outcome of an "easy adventurer world" is that it would look more like an apocalypse with battle scarred farmers huddled in Bastle Houses with militia watching a sentries from behind fences and thorn bushes and the king's army making patrols further out for Goblin, zombie, Troll encounters.
But for me the fun has always been acknowledging the contradictions but trying to work out a way that makes sense, for a relative use of that word, anyway. With that out of the way I suppose I should get started and my apologizes if this is even more rambling than my usual posts.
The Goblin Threat
The meat and potatoes of this discussion. Just how dangerous are Goblins and how frequent are their raids. Something the anime gives us competing ideas about. On one hand on a single day the Guild Hall, as Bear Ribs so elegantly observed, got three separate quests for Goblins before he'd even arrived for his daily check with two more being mentioned later. And he's quite right this is alarmingly high if these are all occurring within a few miles radius of the Guild Hall. If that scale was representative of all Goblin attacks people would be up neck deep in the critters. Yet people act like the exact opposite and we're explicitly told most people only experience with Goblins is frequently chasing off the odd day wanderer.
Now it's possible the Guild Hall example isn't representative. Earlier in the episode Goblin Slayer makes the comment he's had a lot of work lately in response to his rent payment being heavier than normal and later makes a comment about their being an unusual amount of Goblins. Which suggests Goblin infestation is on an uptick possibly connected to the wider war between the Races of Order and Chaos...or just some Gods being dicks with their tabletop game and finding GS of interest.
Further not all Goblin quests are of the same severity. The old man who posts a quest in episode 2 states
From the sound of it the Goblins didn't attack the man's village, otherwise his worry the goblins would eat his cows and burn his fields sound kind of callous, so much that he's found tracks that Goblins came to or near his village, much like GS searches for each day, and now he's afraid not so much for his life persay as his livelihood. Making the Goblins sound more like a pestilence who will destroy/devour your stock and harvest rather than a village razing doom.
This is also the man who acts as if Goblin rape is more a rumor gossiped about than a daily fact of life.
Later Guild Girl gives GS the three Goblin quests she has which would no doubt include the old man's quest from earlier in the day. The details we're given is that one is a "swarm in the western river village", possibly the old man's from earlier, a second is "a small nest in the southern forest" and the third is "an old mountain fort that's been claimed by the goblins". This last one we're told has kidnapped at least one girl and a previous adventurer has already failed to save her. Which may indicate neither of the previous two quests involved actual raids and kidnapped girls.
Further it suggests that even "new" quests at the Guild Hall aren't really that new. Someone has already taken the quest, died and been gone long enough for people to realize he isn't coming back. We might surmise the original quest-giver first posted this quest at a smaller, more rural Guild Hall and when that failed to get traction he then hoofed it to the town in hopes of reaching a broader range of Adventurers.
Further the quest themselves seem to spread across a very diverse topography with the mountain region in particular almost certainly a fair distance away across difficult terrain from either the Guild Hall or Cowgirl's farm.
Lastly the fact the mountain fortress quest was given by the brother of the kidnapped girl likely indicates that this wasn't a full on village destroy attack otherwise it would be doubtful anyone would be around to post a quest or at the very least Guild Girl would have brought it up when mentioning there has been a "few casualties".
Taken all together we might conclude that your typical Goblin quest is a relatively preemptive affair with farmers posting bounties in hopes of preventing loss and destruction. Either discovering tracks near their villages or discovering where a nest of Goblins have made their home and wanting the fantasy equivalent of the Orkin Man to come take care of it. With a smaller subset of those being "come save the girl" or "avenge my destroyed village" types.
Transcript of dialogue taken from here:
Goblin Slayer: Season 1, Episode 2 script | Subs like Script
The Bandit Problem
Of course Goblins are just one threat, possibly even a minor one, compared to the cutthroats, trolls, Ogres, Dragons and slimes which we know inhabit the Goblin Slayer universe. So even if Goblins aren't marauding and destroying villages left and right, why hasn't everything else stomped the poor farmers flat?
To answer this does force us to move more firmly into straight up speculation since anime especially focuses almost exclusively on the menace of Goblins with references to almost everything else far from the focus.
We do know that unlike Goblins there are no shortage of volunteers for taking on the likes of Dragons and other fierce foes either for the monetary gain they promise or the experience and prestige which will allow Adventurer rank up in the Guild. With most quests seemingly being completed within a 24-hour cycle based on how the rush to find new quests seems a daily ritual. So a Dragon that has taken roost within the area watched over by the Guild Hall will likely be dead within the week limiting how much trouble it can cause.
I would submit that quite unintentional and almost accidental the King, Lords or Merchants who are offering the large rewards to protect their own interests from the bigger, more threatening monsters are inadvertently shielding the lesser folk. Both in the sense that the 20 bandits Spearman defeats to protect a merchant can no longer go on to terrorize villagers but also creates an unfavorable risk versus reward. That attacking a small, poor village gives you little for your time and trouble while ensuring every Adventurer who needs a paycheck that week will come gunning for you.
Which isn't to say villages aren't ever razed, they almost certainly are. Your are going to have that Ogre that is hungry and isn't thinking of anything past eating your cows or the bandit troop who think your daughters would make fine play toys for the company and damn the consequences. It is just these happen irregularly enough and are spread out wide enough its a more ignorable problem.
Farm Organization
Farms in Goblin Slayer, whether singular homesteads like Cowgirl's farm or villages like GS's home, seem oddly dispersed and decentralized with much of the country side they occupy being lightly cultivated in terms of civilization and are seemingly surrounded in all directions by verdant, almost untouched wilderness and old, long abandon forts. This I speculate isn't accidental but a deliberate choice on the part of the ruling class to spread the risk relatively wide and far.
The power scale of the Demon Lord's army means that it would be impracticable to try and fortify a farm against them. Not only is a Ogre-Mage tall enough that the windows on a Bastle Houses are about eye-level he's likely strong enough to smash through the wall. Short of turning each farm into its own fortress-city any defenses would likely be a waste of time and trouble. Something the human realm, showing signs of being resource strained, can ill-afford. It also has the problem that while it likely won't stop a dedicated attack from the forces of Chaos such defenses would be very effective against the Crown requiring heavy resources to overcome. So there are certainly incentives not to encourage the peasants to fortify.
The Guild of Adventurers provide some protection of course but it isn't absolute and is firmly outside of any single authority's control. Due to its nature you could have the Guild fixating on the Dragon that week hoping to "level up" and ignoring the bandits setting farms ablaze. So instead the human realm spreads its farms out making each one less individually valuable and making each one less critical should it be attack reducing how tempting a target they are.
A deliberately part of this is the lack of any central authority, Regent or noble to these farms but rather their just vassals working their little plot of land out in the woodlands. There's simply no one there important enough to attack, no wealth to attract thieves or bandits ect.
Broadly speaking I'm imagining a spokewheel design with a town at its center as a hub of trade and a widening spiral of dotted farms expanding out from it in ever greater lengths. For more perishable products, like Cowgirl's cheese, are situated within a day's travel to the town while others, like GS village, are spaced much further out where travel to the town is infrequent. After all Cowgirl was excited to visit her Uncle's farm as a child partly because she was going to get to visit the town.
We know both the human realm and the Elves make use of animal drawn wagons, Cowgirl's uncle even uses one in the flashback, so its likely not every farm relies on busty anime girl power to move their goods. With the idea being each farm will independently send its wares to town to be sold which in turn will be centralized and transported from there to where its needed. The towns would also be the ideal place for the textile mills and other process-involved industry for turning raw material into sellable product.
The end result of all this is that while the overall system is inefficient requiring much more effort to move and ship goods its more resilient to attack, which being a kingdom at war likely is the primary factor, while the farm less appealing targets for all parties involved except Goblins who require human females to breed.