First of all congratulations and I wish you the best of luck.
I'm going to write as one of the many managers of Port in LSRP-SAMP, so this going to be one of those "Too Long Didn't Read" type of posts. Though perhaps GTA V going to be whole different story but still I'd like to share some of my experiences that might come in handy for you as manager.
I'd say it is highly dependent of the manager/player when it comes to control the role-play such faction. If you consider fun you'll need to lose realism and if you focus on realism you'll lose the fun, therefore, it is your duty to balance this duo. All the these things people have mentioned above used to happen in Port back in our days, it just shows how uninvolved they were.
What type of background your character has (Illegal) shouldn't effect your position as head of Port, you cannot ignore the fact Port is a fully legal work and with strong State Service you and the longshoremen would be under surveillance, however again it depends on how much realistic you want to be or could be when you approaching this type of role-play.
That being said that does not mean doing illegal work is impossible within Port, I for example had illegal background while managing the port and have done couple of illegal things with all the role-play I could to not to effect my legal characteristic ICly in any way.
There are few notes you should remember,
When you are choosing your right wings and people who help you as management, try to bring up and give the position to the people that would mostly focus on legal role-play. WHY? Because port is the place that is going to be open-door for everyone, basically every illegal faction, civilians, ect going to be there and you would want to control it smoothly, if you share the whole port with your illegal faction (As manager) that is another story and it would just turn into your faction's legal front and Port work would lose the meaning of being for everyone, yet, if you put different people with illegal background you'll lose the control, you'd be struggling with legal matters, (Yet again that's only if State Services or Police Forces and such be all over on this matter, which I believe they should be) You'll be struggling with sudden employee loss that may effect your smooth work.
Illegals characters would only join for the paychecks and don't do anything as Port Worker and you'll have to keep explaining the administrators who keep record on your activity why it is like that and so on. Also many other minor difficulties you'll face yourself. For these reasons I believe your character should be leaning more to its legal side than illegal.
ICly you don't have to be friendly with everyone, it just turns against you and you'll lose control.
It is your duty to keep it fun, hold group role-plays at port, hold meetings with staff, schedule meeting with Police-Mayor-investors-candidates, run convoys around the town and so many other things you can do.
These are what comes to my mind as of right now, I'd just add it up if anything else pop up. Again good luck with this, it is really fun to be role-playing at the Port. Legal or illegal it is good experience. Have fun.
