Maybe Ronald himself is allowing LE to keep it. It is really the only thing that makes sense to me. If he had even a monthly contract, the house would legally be his as long as the rent was paid up to date. Most rent is due on the first of the month and she went missing on the 10th. He would retain control until the end of 30 days unless the contract was for six months or a year.
Ron has no rights. He's a renter. The owner can say who comes and goes unless LE has taken over the crime scene, which is what I suspect has happened.
ETA: Why does Ron and Misty choose to live in a tent, when friends and neighbors would surely open their homes to them?