This essay is adapted from a post I wrote to the rec.games.frp.adnd newsgroup responding to another poster's question about running a game outside of the usual town-dungeon continuum of most fantasy campaigns. It applies not only to the Septentrionalis setting but to any unconventional gaming world.
It's a problem I used to struggle with whenever my characters were not in a controlled environment like a dungeon. It boils down to this: you can't possibly fill in every little detail, but you can't railroad your players into only going where they're supposed to either; pretty soon, they'll resent it, because the point of a RPG is to have a choice about where to go and what to do, or else you might as well just play Candyland. And random encounters feel too, um, random. Here's a reasonable solution, one I've adapted to all three of my campaign worlds. I'll use a city adventure as an example.
1.Divide your map of the city into several "zones" of irregular size, with each zone corresponding to a quarter, a neighborhood, or a sector of the city. Don't worry about street names, individual houses,etc. For example, you might have: the Waterfront, Dogtown, the Hill, the Necropolis, the Foreign Quarter, and the Palace.
2. Design each of these zones exactly as if it were a room in a dungeon. First, describe it as a whole, the look and the feel of the houses, the narrow streets, the smell of boiled cabbage, the demeanor and appearance of the inhabitants. For example: Dogtown: "You enter a neighborhood of narrow streets and half-timbered houses whose upper floors hang over the street as if contesting for what little sunlight has managed to penetrate the smoky air. The streets are deserted by day, but at night, almost every doorway and front stoop is occupied by one or more shadowy figures, and the alleyways seem like dark portals leading to the underworld." You get the idea.
3. Next, put in a monster or two, just as you would in a dungeon. For a city adventure, two or three powerful NPCs per neighborhood are sufficient to act as the local "monsters". The key word is powerful. Just describe the movers and shakers, not the candlestick makers. For example, Dogtown might be the home of Devin, King of Thieves; Gamleel the Necromancer; and Spythus the Snitch. You can assume that the place has plenty of cutpurses, fences, gamblers, drunks, and beggars, but most of them will be under the control of one of the powerful NPCs, so just consider them extensions of those NPCs. In a good campaign, nothing happens randomly, even if it seems so at first. You're the boss of your world; if you think the campaign would be improved by bringing Gamleel into it, do so by putting a beggar into the path of the players who just happens to be one of Gamleel's bodysnatchers. If the campaign is going OK already, just let the party get through without incident and on to the next neighborhood. My players have come to suspect that my "random" encounters are always potentially meaningful, so they listen up whenever I describe an NPC. That's the best way to keep them interested, by having no insignificant events. The key is not to let them know just what the significance is right away.
4. Instead of treasure, sprinkle a couple of significant locales within each zone. Instead of gold and jewels, "treasure" in this context means anyplace where the characters are likely to receive information about the power structure of the city or to gain access to the powerful NPCs. So a tavern where Devin hangs out is potentially valuable for the party, because maybe he might hire them to do a job, or maybe they can try to take over his operation. Don't worry about where exactly the tavern is located; in a city, you can get from anywhere to anywhere, but the key is knowing where the centers of power are. Like treasure in a dungeon, significant locales are seldom in plain sight. So assign a difficulty value to each locale from 1-20. If the party is unaware the tavern exists, roll a d20 each time they enter the neighborhood, and don't introduce the tavern to them unless you roll at or above the difficulty value of the locale. If they've hired a guide, or have a native citizen in the party, give them a bonus to the die roll. Once they have found the place, they should be able to find it again on subsequent visits.
5. So now you have a city made of several "rooms," each with its own atmosphere, "monsters," and "treasure." The party can move from zone to zone, just as if they were exploring a dungeon. Instead of fighting monsters and getting treasure, the idea is to crack the city's power structure and get influence or favor. Within this framework you can place more traditional "dungeons," most likely the lairs of the powerful NPCs, but only if you feel a need. I have run long campaigns on the above model, centered entirely on the intrigue between the various power brokers.
I handle wilderness adventures the same way, by breaking up the wilderness
into irregularly-sized zones, each representing a different area, like
the Forest of the Ents, the Great Dismal Swamp, etc. I eschew hexes and
grids entirely, and just assign each area a number representing the number
of days' travel it takes to cross it, plus or minus d6 days. Each area
has one or two powerful monsters or NPCs, and if the drama of the moment
calls for it, the characters will run into them. Otherwise, you just give
them the stock description of the area, and move on. Occasionally I'll
throw in the odd random monster to spice things up a bit, but as a general
rule, whatever happens, happens for a reason. Difficult terrain areas might
also be assigned a requisite skill, like "Mountaineering" or "Woodland
Survival" or "Ranger: level 2 or better", which a party member must have
to enable the party to enter the zone. NEVER get into the nitty gritty
about individual streams, copses, glades, paths, hills. Just stick to the
overall atmospheric description, and make sure each area has its own distinct
character.
For example:
"You enter the Forest of Nightshade, and find yourself under a thickly
woven canopy of green leaves. The deitrus of many autumns crunches and
scuffs beneath your boots. Marcus the Ranger leads you through many ill-marked
footpaths, skirting deadly briar-patches, and the occasional sunlit glade,
where a mighty oak has fallen, killing several of its neighbors and opening
the roof of the forest to the blue sky. Eight days later you emerge, blinking
and squinting, with the Plains of Elvenholme stretched out before you."
This mapping/description method has worked quite well for me, and I
hope you give it a try. Please excuse the length of this post; I hope it
wasn't too much work to read all the way through.
Doug