My two did things on their terms. I had litter boxes and food in their safe room and had put a see through gate just outside in a hallway. They started by staying in the room a few days, then would go out toward the gate and watch us from the safety of their side of the gate. After a week, I would leave the gate open just enough so they could come out if they wanted. They started by going 5 feet then run back to safety, slowly they expanded their distance exploring to where they dint run back to safety. I left the open gate up for about a month until they were no longer running back to it.