Here are two lesson plans based on Edward Hicks:
http://www.princetonol.com/groups/iad/lessons/elem/Jeanette-peace.htm
http://coreknowledge.org/CK/resrcs/lessons/01_Art_PeaceKingdom.pdf
Here are some books on Amazon focusing on Edward Hicks:
Here are some books on Amazon focusing on Pennsylvania Dutch:
I hope you find something you can use in these links. As always feel free to leave any additional suggestions in the comments section.
And I still have plenty of winter kits left, so if you are looking to get started in a study of Edward Hicks and the Pennsylvania Dutch folk art style, be sure to check it out. In all there are 3 handicraft projects, 3 notebooking pages, an art print with corresponding drawing project, a complete lapbook and a nature journal focusing on mammals in this kit!