Phil Bradley has produced a geological guide book on the Eno River State Park, and in Oct 2015 released another one on Crowder Mountain State Park. Both are available from the NCGS.
Fred Beyer has a mailing list for Earth Science Teachers (http://lists.ncsu.edu/cgi-bin/mj_wwwusr) (put EarthSciTeach into the search box). Look at the titles of recent postings to see if it's of interest to you.
Skip Stoddard has a blog describing the geology of walks in or around Wake County (http://ncgreenwaysgeology.blogspot.com).