This is an attempt to put a couple of my ideas for a space-opera-like setting into a working concept. This is the kind of game (roleplaying or computer) I'd like to play, although it seems I am condemned to run it as a referee, or to write the stories myself. So, here we go...
The basic concept is that of the independant merchant liner in a semi-developed sector of space. There is a group of characters running a ship (or a freight line with several ships and/or facilities) with contracts to deliver material to certain outposts of mankind (and/or friendly or at least neutral aliens), through less friendly terrain (caused by the hazards of spacefaring as well as the hazard of unfriendly spacefarers).
The group runs their trade along certain, publically known "jump routes", and a couple of less known ones. This means there is a limit to "free-jumping FTL navigation" imposed on the technology used in the setting. Several models offer themselves to explain these:
A short aside about our Starwars campaign: we are playing in some near future after the battle of Endor, with the New Republic and the resurging Empire still at odds, and a couple of worlds and rim sectors in between, and bearing the brunt of the conflict. There are ancient artifacts, unknown technologies of unknown civilisations, which interest both sides as well as crime lords and criminal clans.
Actual events aside, the group has an almost standard border region freighter with a considerable amount of debts, a couple of valuable but hardly legal cargo units, and a couple of considerable bounties posed on their heads.
My problem to reconcile this campaign with the general idea above (secret jump routes) is the established fact of free jumps from WEG's Starwars RPG. The only region which has anything remotely resembling the establishment of jump routes is the Kessel Run, with a series of singularities impeding the jump routes to and from Kessel. A similar effect might be had in a cluster of suns, neutron stars, and/or raw stellar matter which might have interesting economical opportunities. (There is one such phenomenon described in Platt's Starport guide, but only for a small sector (a single system if I recall correctly), my concept would require an entire sector subject to these conditions.
So the region I want has to be full of debris and gases impeding FTL travel (as well as sublight), a couple of well-developed jump routes along jump buoys through corridors of less dense impediments. Micro-black holes migrating through the uncharted debris and black bodies pose a threat to uncharted flight.
Why have jump buoys when the average (early New Republic) Star Wars ship has a nav comp? There are a couple of good reasons. A nav comp will give a route only as good as its astronomical data, i.e. its passive long range and active short and medium range scan. Naturally, a stationary receiver scanning long range over a prolonged period will have a better set of data than a ship just having jumped in and about to jump out on short notice. As for active scans, a ship entering a buoy's space will be able to scan all the distance to the buoy with no difficulty, plus a lot of (usually empty) space away from the buoy, but the buoy will have scanned all the critical environs, plus (unafraid of being detected, and built for it) will have a lot more medium range scan data. All for the sharing, so that you get detailed nav data of all ships present in the buoy's scan range (unless edited somehow).
The buoys provide both navigational data and a focus for the FTL jump (aka "tach" in spacers' slang) - according to the Star Wars FTL description on the Technical Manuals webpage, STL objects are detectable as smears in the FTL phase - a steady emission of a certain signature would be traceable in FTL phase, and should be useable for conditioned entering/leaving tach. Most inhabited worlds and stations have a "natural" homing signal anyway from their "radio heat", the amount of broadcast and emissions of a technical society. On certain wavelengths (prescribed by the physical facts of oxygene-water atmospheres predominant in the known galactic civilisations) an inhabited world will emit more energy than a sun... and we all "know" that suns can be detected in tach.
The buoys are regularly patrolled to deter hampering, ambushes or false buoys rigged by others. Ambushes are practicable where the active scan of the buoy is impeded by natural obstacles (usually debris or energized matter) or by shrewd "electronic warfare" devices. The easy way to prepare an ambush is to simply drift into medium scan range with energy low, which will register the physical object but won't register a ship. Electronic warfare uses specialized "virus" transmissions on the ships' ID channel which may fool the processing unit behind the scanning devices if sufficiently subtle. As long as the "cloaked" ship remains largely inactive, the sharade can fool the detectors. The more active a cloaked ship becomes, the more sensors will receive their data, and might actually override the desinformation that "there is no such ship there". This works more like a cloak of displacement than a cloak of invisibility, to use Nethack terms. Of course the sensors can be blinded by an energy overload, but that is both costly in energy and will invite close investigation by all interested parties.
The Crashlander will soon(ish) get the opportunity to operate in and out of the Tenebrae Nebula. This nebula lies close to their former area of operations but is a bit removed from their last activities. Both New Empire and New Republic have their interests in the fringes of this Outer Rim "sector" which is dominated by the debris of a couple of proto-stars forming in the remains of a cataclysmic collision of a minor cluster of stars with this galactic arm. A triplet of pulsars provides part of the sector with an eerie glow which unfortunately hampers FTL travel where it occurs in greater amounts. Generally speaking, the denser the residual matter in this sector, the stronger the glow, but the glow is a result of the pulsar radiation and will ebb up and down in complex and not entirely calculable patterns.
Astrogation in the nebula is quite simple as long as one remains in the rifts between the proto-star tendrils, or moves outward from the worlds and stations along the fringes. Both Empire and Republic claim part of the coreward space for their own, and maintain military bases. Both are interested in the superior shielding material provided by the mines in the impact debris, though only in small quantities. Either have established processing plants on worlds nearby.
(Campaign info: it takes five weeks' jumping with the Crashlander to cover the distance between their last port and Tenebrae Major, a huge gas giant twinned with a minor sun circled by numerous colonized moons and stations. Tenebrae Major has maintained friendly relations with the New Republic without joining it outright.)
Tenebrae Nebula has seen quite a bit of conflict during the recent wars. The Thrawn Renaissance of the Empire was the latest source for destruction here. As a result, there are ruined and abandoned colonies and stations, and secretely retaken ones as well, plus hidden refuges slowly running low on essentials.
The New Republic wants to hold on to what's left of Tenebrae because it sits quite close to a good entry route towards the Core Worlds once one has gotten through. The Renewed Empire wants to close Tenebrae for the same reason. Strangely, this makes them more fond of the jump buoys than the Republic because these keep traffic controllable to certain main routes, simply by placing them in critical turning points between jumps. And of course they produce trace data on all ships passing through, if one knows how to tap this info. The Empire does, and the Bounty Hunters know where to pay for specific access to such data. As a consequence, the Empire has put some efforts to patrol the buoys, keep them clean (and read) and remove competition by other sources. The Republic has a series of own routes patrolled and overseen by their forces. Independent stations of variable sizes function as buoys if one knows their codes and general location.
Various derelict stations or buoys keep sending their general signature, and while somewhat useful for orientation for well-developed astrogation comps, provide no knowledge about safe jump routes. As a general rule, a buoy's homing signature grants safe tach passage only from certain other jump-off positions. Ships wanting to avoid notice by the buoys usually jump short, or use "electronic warfare" devices, crawl around the buoy in an additional jump or evasive course, and home in on the next buoy. Signal dispersal will reduce a ship's signature over sufficient distance. Ships on urgent illegal missions often will make a couple of registered jumps before obscuring their passage.
The inhabitants of Tenebrae mostly have a neutral stance to both New Republic and Empire, preferring neither. This goes even for worlds thoroughly controlled by one of the sides, because both sides have committed grave crimes or excessive activity in the recent wars. The native worlds would prefer to be autonomous, but not for the price of yet another terrible war. Certain organisations act totally outside of any side's control, and the hidden colonies try to do so as well, even faced with domination by the criminal elements in Tenebrae.
A survey of the Gemini sector of Wing Commander Privateer game resulted in about 20 of 60 systems positioned on nodes between the jump routes, covering only one side (the humans) of the human-Kilrathi conflict, and offering harbours for illegals in between.Translated to Tenebrae this means that there ought to be about 30 node worlds in the nebula region, and about 20 worlds just outside used as jump-offs into Tenebrae. Off the main routes there would be about 60 worlds (inhabited planets, major stations, or both) of interest generally known, and perhaps 40 known only to select customers. Add hideouts in spurious debris around insignificant suns and insignificant nav buoys, and the Tenebrae Nebula neighbourhood will contain about 400 places of interest, including destroyed colonies and ships' graveyards. More than any campaign can ever hope to explore in depth, enough to keep a need for all involved to rely on incomplete data, few enough to give at least some minimum information.
The Tenebrae Nebula sports a couple of major highways connecting the major worlds and regions. These routes have sometimes fanciful names, but usually are called the so-and-so run after the most important resting points.