There were interesting tidbits of historical material thrown in here and there (but not in any systematic way, and usually greatly disguised), but mostly this is Ackroyd musing, creating his own Paradise Lost and putting Milton right in the center of it. He's captured quite well the tensions between English settlers of different religious perspectives and the original inhabitants of the area.
The narrative thread was sometimes rather difficult to keep hold of, and frankly I thought the idea of this book somewhat better than how it ended up being carried off. Nonetheless, a worthy premise, and certainly it's fascinating to think about how things might have gone had Milton in fact crossed the Atlantic and made a new home on this side of the pond.