Another still-in-progress plan here. American History.
We like the pages we've printed off so far from History Central's website.
We'll start with The Age of Exploration...probably using many of the links and ideas from their listing of chronological exploration of North America. I know these aren't all-inclusive links, but it does give us a good starting point and we can branch off into other areas from there, like a specific study of a time frame, or a particular explorer, etc.
And read-alouds, of course. They are a backbone for us this summer at least.