After June 6, 1942, the lands acquired for the Acadia, French Creek, Shenandoah, and White Sands recreational demonstration projects shall be added to and become a part of Acadia National Park, Hopewell Village National Historic Site, Shenandoah National Park, and White Sands National Monument,¹ in the order named above, subject to all laws, rules, and regulations applicable to the respective areas to which such recreational demonstration projects are added.