[Timolas]

It sounds like you have been doing a bit of this anyway, but I think it really helps to start with the question "what kind of game events and scenarios will I and my players have fun playing?"

If you want a lot of star hopping, and in a Firefly / Han Solo (aka the good bit of Star Wars) sort of fashion, then you probably won't want a single journey to take more than a week or so. Long enough for interesting things to happen en-route, but not so long that the crew are forever climbing into the hibernation pods.

If you want interstellar travel to be special however - and arguably it is the most special thing IN a space game - then longer trips, requiring more infrastructure - like your space cannon - are more appropriate. In such a setting I would suggest it is unlikely that the players own their own starship; instead they might be assigned to it Star Trek fashion.

Your notes suggest that this is the style you are looking for more than the tramp freighter version of space opera, and that is cool... But just be aware that you'll be making it hard for your players to operate fast and loose with the authorities, should they want to. And in the worst case, they may feel a little without freedom, if travel becomes too difficult. Basically it becomes less a case of them saying "where shall we go next?" and more one of you setting up a series of scenarios linked by the few feasible routes they can take through your universe.