There has been a lot of discussion about Space Combat Operations, and we have a lot of sources to draw upon. In some cases these are contary, or can be interpreted in different ways, therefore I will try and combine everything there.
2300 and SC give 4 different scales of insystem speed, however, the only one that seems to work is the 6.45AU/day scale, and there's why:
The question is whether partial discharges are possible. If you travel 5ly, want to travel another 5 ly, can you just discharge 2.3ly, and use the remaining 2.7ly of range? I'd say yes, for no real reason other than I prefer it.
How much data does a gravity scanner provide? This was debated at length, and people with Physics PhDs threw in and gave a very good description of how they'd work. Gravity Scanners will tell you how much stutterwarp activity there is within their range, but will not provide range and bearing data.
A typical output from a Grav Scan might look like this:
Drives Insystem:This output shows a bunch of Merchant ships/ small craft insystem, plus 3 Kafer Betas. Knowing 3 Kafer Betas are insystem, you can go looking for them.
17 1MW drives
34 2MW drives
71 3 MW drives
30 4 MW drives
6 5 MW drives
1 20MW drive
3x 200MW drives
Deep System Scanners
Capable of detecting operational power plants at upto 1 AU. The DSS is the source of the Black Globes on the SC map. The range is probably not much more than tactical ranges and the DSS is not really useful as a search sensor (A 150MW power plant radiates a lot less than a planet, detected at 1AU).
Chokepoints and Sentinels
Every system contains a series of Chokepoints, generally planets, which control of is required. Planets are used for discharging stutterwarp drives, and if you loose control of one, it becomes possible to bypass the system. The logical solution is to station picket ships at each chokepoint, but military starships are not numerous enough for this. Instead both humans and Kafers employ "Sentinels". A Sentinel is a drone with a passive scanner and a det-warhead, it sends a squawk out if enemy traffic comes near and shoots at them.
Pickets outside of the FTLT will be jumped, the enemy will simply appear quite close. On the other hand, the opposite is true, a reaction squadron ("The High Guard") based at the FTLT can jump them there. Inside the FTLT picket ships can see the enemy coming and fight holding actions or withdraw.
There is a way to sneak through a fully blockaded system, discharge at the Star. Either that or fool the Sentinels. It's possible to sneak a frigate or well designed destroyer through an enemy infested system, but not a honking big Cruiser of the Line.
It is possible to track a starship between the stars using Grav, as long as you stay within 150AU. The Grav scan, once outsystem tells you whether the target is more within 150AU, so you can try and stay in this zone. To prevent this most ships "dogleg", depart the system on a radically different vector and then turn towards the target in interstellar space. Tracking a ship is quite difficult, but possible, and is mentioned in Lone Wolf.
Detecting the Enemy
Okay, we know the enemy has entered system, how do we find him? The ways we can find him are:
Once the enemy is detected, SC action occurs until contact is broken.
A short word about this. Ships are going to have limited ranges, even
without a fuel limit, refits are required fairly often (about every 6 weeks)
which require either visiting a base, or doing it yourself. Without maintenance
like this ships will become less effective.