Also... those forts at either end of Cuba on their own islands. You can get by them by staying as far away, using your fastest speed, and avoiding the mortar fire. They will try and shoot you within 500 meters, but I was able to get by fine earlier in the game. That being said, you don't have to, everything you need IS in the north.
i found that the quickest way of making wood and metal and sometimes cloth too is by finding naval convoys around your map.every convoy will nalso give you an amount of reales from 2000-10000 which is really useful too if you cant find any naval convoys then go to taverns located around your map and ask for information this will cost you 200 reales [money] but u will be able to attack this convoy and get lots of metal and wood usually about 100-200 of each please note that asking for information will some times end up showing you the location of cadavers instead of convoys but other than that wairhouses are a fun and safe way of collecting wood and metal especially the one on cat island