Thats about it, once the war is over its over. If you try to stay out to sea, eventually you will run out of fuel/ammo and need to dock which will end your career.
Although as i type this i wonder if you just kept going to Milk Cows to refuel/re-arm and stay away from ports if there is a chance you can continue playing. I have a long way to go in my current career before i can attempt this but if anyone is currently near the end why not try it and report back your results.
