I have finished my previous rulebook I was working on, and have begun the research for the Hernando de Soto one. Starting off with the Duncan's Hernando de Soto: A Savage Quest in the Americas.
I have also finagled a JSTOR membership to get PDFs of academic journals. I'm hoping to find some interesting, current research which will help reconstruct scenarios for the campaign book.
Thanks again, everyone, for the suggestions on miniatures, books, and more!!
Mike Demana