Using the limits I have drafted, there is nothing to stop one from jumping from system to system as fast as you want without entering deeper into the system. There will have to be some kind of cost, but I do not want it to overwhelm the remass cost for entering deeply into the system.
But I have not thought of a reasonable limitation that I can justify against something real like conservation laws or uncertainty theory. I do not want anything too arbitrary. Not only does it smack of artifice, like the Traveller "100 diameter" limit, but it is too tempting to overturn it with a convenient deus ex machina.
It does not need be too severe, either. Just enough to slow things down. I like the idea, in fact, that there is a benefit for having facilities in habs in an outer gas giant. Transports might, for example, refuel at the gas giant on system arrival and departure. Warships certainly would. Bulk traders might never go in-system, instead shipping goods launched between other points in the system and a transit station on a Hohmann trajectory.
I am up for suggestions. Extra points if the answer some how invokes either Boltzmann or Heisenberg. In fact a process involving establishing location and velocity based on pulsars (or the local navigation beacon, which gets turned off in a war unless needed) might do the job if there was some way to justify the time involved on external criteria rather than processing power.