In the 1960s and 1970s Gasteen was involved in surveying and promoting National Parks proposals across Queensland. This was unpopular with many graziers and politicians. He worked to protect remnant patches of Central Queensland scrub but also surveyed land from the Gulf of Carpentaria in Queenland's north to the Scenic Rim on the Queensland/New South Wales border. His survey work or reports led to the establishment of Expedition National Park, Nuga Nuga National Park, New England National Park, Northern Rivers National Park and Border Ranges National Park.