What's your strategy regarding America's conquer UHV? Do you tend to attack right away and stay in a state of war until 1892 or do you build up an army beforehand? The hardest part I find is knocking out the single-tile settlements in the Caribbean since they require an amphibious landing and you can only cause collateral damage with the relatively weak Grenadier. I find you really have to attack right away or you risk the AI getting ballistics. One way to get around this is to request these settlements in international congresses but that's unreliable at best. Most recently I lucked out and was able to bombard and blockade the cities down to 1 population and timed my attack with an outbreak of the plague so the units were weakened and it only took 2-4 units to conquer each one. Unfortunately, I managed to completely forget that Newfoundland and Labrador counts in the European colony exclusion zone so after knocking out the French, Spanish, English and vassalizing the Mexicans I still failed because there was British St. John's and two Norwegian settlements.