My cat Seamus was feral when we adopted him. We tried to make him an indoor cat but he was clearly miserable. With reservations, we allowed him to keep his own indoor/outdoor schedule. Once he became king of the block, we got used to not seeing him as much. Every few days he would come home for a bite and maybe rest a few hours before going back to his life. We imagined he had an apartment somewhere, and maybe another family or two to check in with. We might see him around the neighborhood while walking our dog and he would always say hi.
As he grew older, Seamus seemed to show signs of wanting to settle down as a house cat at but he didn't know how. We tried to cuddle him but he would scratch. My brother came to visit and sent some time working with Seamus on his issues. Seamus drastically changed his personality once he found some understanding in David. He began sleeping inside and hanging out closer to home. He even let us pet him some and would snuggle a bit. It had been over a year of life with the new Seamus when he disappeared again. After four days we were pretty worried, though the old Seamus had frequently disappeared for longer. I was resigned to go the next day to the pound to look for him, when I heard his squeak at the backdroor. He was home! And pretty dirty. It seems he missed his feral life.