The challenge, should you accept it, is, with any PoD no earlier 1640 make the Atlantic side of North America to host the bases of two powerful rivaling english speaking nations of the region. One should be theocratic puritan calvinist nation, while the other one is basically British dynasty in exile, for whatever reason. Both nations must :
1) be at least regional powers
2) be in a kind of antagonism with each other
3) NOT be possessing Britain, nor setting a military presence there
4) NOT be filling North American continent all by themselves. At least about 20 % of North America must be outside of both nations' direct rule.