This post (about the book American Apocalypse) has a helpful framing of different interpretations of American evangelical history. At least you can get a sense of different interpretive traditions. I read Sandeen and felt he overstated millennialism’s role (and don’t think he got a few other things right). Marsden was the major figure I studied, and I appreciated his more complex understanding of things. But I think it is true that there were other strains not captured well in Marsden’s approach. I’m not convinced that this new model is quite right either, especially as in my reading I’ve seen a more complex apocalyptic framework. But I have to read it first. We’ll see.