Remember the trick of the 1000 gold per sailor recruited, so as to keep them at minimum status Unhappy, but be able to sail and work with them indefinitely (if you don't divide loot)? You can expand upon it. If you also have a small fleet of select, best quality ships fully upgraded, so as to have room for LOTS of food, you can cram your ships full of crew and start sailing the seas for YEARS!

A challenge for the greedy, then! How about raiding ALL cities on map and having them change hands, to the nationality of your choosing? I, for example, started converting everything to DUTCH! A bit repetitive, especially the land battles, but this way, you can play the strategy game you always wanted, turn based, too!

So as to be fair, because the targets are many, you can:
1) Use pirate havens and Indian villages to target a city, so as to soften it for siege.
2) First finish quickly all quests, in no longer than 20 years total.
3) Attack "invasion force" ships, "military payroll" ships and "transporting troops" ships, so as you won't have to face a battle of impossible odds, later...

If somehow a city is raided by another nation while you are away, remember to retake it quickly, while it is empty of soldiers, before a settlement sends troops or any other hindrance. Settlements can spawn "Invasion Force" and "Raider" type of ships, sometimes, even though they are not fully functional cities... Also, you can attack land-exclusive cities, like Panama; get off the ship and march there! By the way, Panama is the strongest city ever; 500 soldiers and no way to reduce the sum!

This time before i retired, i conquered everything on sight, the Caribbean became a pure Dutch land! Yarr! But now i am forced to retire, since there are no enemy nations in play and i intercepted all invasion force ships... But maybe i can live off bashing pirates, since time passed and the next time period (golden age of piracy) is well in play, the sea is full of double and triple pirate privateers!