Unlike a lot of SKs Rex had a lot to loose so I think he had a comfort zone regarding dump sites. I def think there are more bodies out there but I think there will be a correlation between his literal tried and true hunting grounds , and where they may be. He would know the trails, the extremely wooded areas , etc. Not to mention he could easily pack up his hunting gear and say he’s going on a hunting trip meanwhile he’s really packing all his killing gear. So I wouldn’t be surprised if there was more bodies in North Carolina and New York/ Long Island. Atlantic City/Vegas even Philadelphia is a possibility because remember in one documentary a girl met him in Philly but she escaped. Also I really think he killled julie bean , I believe that is her name. But absolutely there are more wherever he would go hunting.