If the economy collapses, how do we grease the palms?
I'm worried they'll kill us and take our sluts.
Assuming we have the resources to build and maintain this fortress, I'm further assuming we can acquire certain things that would be of use to the crew of an Aegis cruiser that can't easily forage on land for what they need. The first and foremost that comes to mind is fuel, without which they're dead in the water anyway. Other possibilities include food, drugs, precious metals, sanctuary within the fortress if need be, and the ever-popular rum and whores. (We can auction off women we're sick of and they'll think it's payment.)
I'd further recommend that we place mines near our coast to prevent landing by unauthorized personnel and to head off that "they kill us and take our sluts" possibility. Then the people in our area who know where they mines are planted gain a significant advantage.
Failing that, in the event of likely hostilities, I'd suggest we send a zodiac off with an escapee to seek sanctuary on board who doesn't know that the craft is wired with plastic explosives.
Alternatively, if we plan far enough ahead, a small team of saboteurs on board before hand ought to be able to bring about a false alarm evacuation. Given recent threats, a fake nuclear contaminant seems like a good scare tactic. We could probably scavenge enough radioactive materials from civilian sources to make a Geiger counter crackle convincingly, and be long gone before the rafts full of sailors realize they were evacuated for a shoebox full of old radium-dial watches.
Just brainstorming.