Quote from: RPGPundit;1131156My Space Opera game Star Adventurer presumes some form of hyperspace travel for your ships, though in the space navigation and starship combat rules I make it easy to skip that if you don't want it.

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Had a few thoughts for the FTL drive as listed, and things that could affect it:
* Mass of drive needed - is the ship just a thin shell built around the drive, or is the FTL (i.e. Battletech where the FTL core for the civilian vessels takes up 95% of the ship's mass) a simple refit that can be added to anything (similar to ST:TOS where the Enterprise crew stole a Romulan cloaking device that was about the size of a person)
* Quality of drive - how close to the calculated arrival point the ship will arrive.  Higher quality drive will arrive closer to the calculated point, but be more expensive.  Merchant ships might be willing to accept a lower quality drive, and a longer trip, while military units might want tactical jump capability
* Quality of FTL computers - better computer can give you more precision in the jump, and/or perform the jump faster.  Larger ships have an advantage here as the computer cost for its accuracy will be a fixed value, meaning larger ships get more benefit from it
* Accuracy of database - you are jumping to another star system, hope the star charts are up to date, and nobody messed up the data.  It's be annoying if you got the planet and its L3 point swapped
* Sensitivity of drive - will external effects cause drive issues?  Can groups deploy 'jammers' that prevent arrival or departure jumps from occurring within a certain radius of the jammer?  Preventing arrival means an attacker can't just jump into planetary orbit and drop nuclear warheads, while preventing departure could be used by pirates or coast guard vessels to prevent a ship from leaving
* FTL Jump 'noise' - does the FTL drive cause any EM signature when it arrives or leaves?  How big is the signature?  Is the signature proportional to ship width/length/height or to ship volume?  If a small signature, that means smaller ships can arrive much sneaker, meaning planets have to watch out for raiders popping in to steal stuff or drop off sabotage crews.  If large, what prevents an attacker from using drones to perform EM attacks on defenders before attacking?
* Fuel consumption - how much go-juice does the ship need per jump?  Is it like Traveller with massive fuel tanks, or are the fuel requirements smaller?  Is the amount used based on ship mass, ship cross-section, distance, or?  If based on cross-section, that gives larger ships an advantage since they have a larger volume for their cross-section than a smaller ship.  It also encourages narrow designs to reduce fuel usage (but narrow designs can have structural issues if too long for their width)
* Physical limitations - can the drove work if there is a solid object between it and its destination?  How much solid matter needs to be rersent?  I.e. imagine a system getting ready to invade another, but the target system has a gas giant in the way.  Will the gas giant prevent the jump drive from working, will it deflect the drive, or will the gas giant be ignored?

From there, you can have various cultural rules for usage of the FTL drive, so someone going into a new system might first go ~1 light-week away from the star, ad try to determine the system plane.  After determining the system plane, the ship will pop in above or below the poles of the star, and deploy sensors to see if anyone is present.  If they talk to someone, they use the local's rules about where to go.  If nobody responds, they may go to the L1 point between the star and the selected planet, and proceed from there.

One idea might be making the FTL fuel consumption be based on ship cross-section, and proportional to distance.  So merchant freighters are large cylinders, and smaller ships often hitch rides with them.  Those merchant freighters travel a fixed schedule, allowing the GM to say there is no transport available for X amount of time, unless the PCs want to use their own ship.  These merchant lines are not attacked by pirates, as the bounties paid if anyone attacks a Merchant ship are quite high.  But ships leaving the Merchant freighter and en route to the planet can be attacked freely.  This allows relatively cheap cargo and passenger shipping to occur, while the fixed schedule means that if an NPC needs to send freight to a specific planet, they may need to hire the PC group to do so.

Hop this helps

After thinking this over for awhile, realism isn't the best thing to base your game's FTL on. FTL in a sci-fi game is similar to magic in a fantasy game in that it needs to be designed last in order to fit the themes and scenarios that you want for your upcoming game. Not only can your FTL method be a central plot element, as it is in Dune or 40k, but even if it's not, it still determines what sort of adventures that can take place in the game.

Star Trek, for example, is an Age of Sail setting. FTL is relatively slow as the captain of the ship sails through space from island to island. Because of the slow nature of the FTL travel, the captain is often "the only ship within range" and will need to take care of whatever situation is going on in the area he is traveling through, whether that's a military, scientific, or diplomatic adventure, the captain as his crew will need to take care of it, usually without outside resources.

The same isn't true for something with near instantaneous FTL like Star Wars. If there is a diplomatic problem in a game with SW-based hyperspace, there's no reason for the party to deal with it as 15 minutes later a ship full of diplomats will arrive. Instead, Star Wars is more of a globetrotting pulp adventure, with the party traveling from planet to planet in rapid succession. Just imagine watching Indiana Jones and every time they show the map with the red line moving across it, assume that they are in hyperspace.

That being said, decide what types of adventures you'll want and design the FTL travel method to accommodate those. For example, when setting up my space western, I decided that FTL travel would be through gates. And, due to the exponential energy for the size of the gate, they standardized gates as relatively small diameter of 30 yard. Therefore, space ships are long and skinny, and travel through  the gates one after another .... space trains.