That was a nice stack of Cavs there in Dover. Made things quite easy for me.
I'm a little short on time, so here's a more abbreviated post than normal.
For my entire turn, after each city completed production, if a city had a Cathedral, Marketplace, and Bank, it went for military. I built Cavs, Cannon, Muskets equally until the end, when I started more cavs going. If a city was missing one of those three improvements, I went for those in that order. The exception being a few coastal cities which pumped a good number of Galleons and a courthouse or two.
Pre turn. - Loaded up lots of galleons and prepared to sail for new lands.
1425: More ships loaded up for the invasion of america.
1430: Ships sail for America, the Heathens will be converted. I rushed a couple of galleys.
1435: Ships sailing, workers working, more ships loading.
1440: Ships sailing, workers working, more ships loading.
1445: Ships sailing, workers working, more ships loading.
1450: All ships required for initial strike reach striking distance of heathenistic American soil. I split the invasion into two task forces, the first striking north into washington, the second landing in the East at Boston.
1455: War is declared, All ships drop troops off within striking distance of their respective targets. Vicious American prestrike, a lone horseman charges valiantly into our Muskets. He is dismissed.
1460: Boston falls easily to our Cavalry. They're defending with Pikemen and spearman. Washington falls after wounding, but not killing a good number of our Cavs. Remaining Cavs in North sortie roll through New York as well.
Vicious American couterattack, a spearman and a swordsman appeared in the hills north of washington in 1460. They were excused without an audience.
1465: Chicago falls to the crack Northern sortie, the Great Lighthouse is ours. A great leader is formed, and I have no idea what to do with him. More later.
The Eastern sortie, feeling somewhat like slackers, pushes west and claims Philadelphia.
India and Washington form a trade embargo against us. Ghandi just made the list.
1470: The Eastern and Northern sortie meet and easily crush Atlanta. I move many wounded cavs into Atlanta to heal for the final push. Though to be honest, there are four fully healthy cavs outside Atlanta which could likely finish the job. Reinforcements from the home land are turned around as they wont be necessary and there are other crusades to prepare for...
Summary. The Americans are toast. Finish them off quickly to prevent annoying flipping. They're defending with Sticks and stones.
For the life of me, I couldn't figure out what to do with the leader. Philadelphia kept its harbour after we took it over, so we didn't need one of those on the island. I thought about a barracks, but that seemed like a huge waste. Armies at this point aren't really necessary. All they're really good for is getting a victory so the Homeric Epic can be built.
Anyway, he's now on a boat south of Boston. He can be used for whatever purpose. If we're going to press this attack into the big continent, use him quickly, rush a temple or something. If we're going to take a little time to build up a bigger force, we may want to hold off and use him to rush an upcoming wonder.
American Island:
The Game:
http://www.civfanatics.net/uploads/GG1-1470AD.zip