As the head archaeologist at the park, Guidon was responsible for the preservation, development and management of archaeological projects in the park. She and her colleagues have discovered more than 800 pre-historic sites revealing occupation of the Americas by human beings, of which more than 600 are accompanied by paintings. In Pedra Furada, Guidon and her colleagues excavated an archaeological rock art site to uncover evidence of a Paleoindian culture they believe to be as old as c. 30,000 years B.P., significantly predating previous theories of the first habitation of the area by early Americans. She has recorded over 35,000 archaeological images and published multiple papers and books.