I had an adult king escape for 6 months, found him by stacking empty beer cans across the doorways, and checking the the next day.
The area with the beer cans knocked over is where you start searching.
If you're lucky you can hear them falling over.
I found him in the crack UNDER the boiler in the basement.
I wondered why he was under there, until I was looking at him, and the boiler fired up. It got nice and warm down there.
I had to hold a mouse by his tail and let the snake strike him, and pull the snake out by the mouse's tail.
He had no food or water for 6 months, and was no worse for wear except a bit thirsty, and covered with dust bunnies.
I had a juvenile escape for over a year, and found him.
He escaped from a 3rd floor attic, I found him in a non-attached garage in the middle of winter, at about 15-20 degrees on a cold cement floor.
He was stiff and cold. They're both still alive today, but the juvenile suffered some nerve damage from starvation and freezing. He can't lift his head up to strike and hold it steady. He can still eat by himself, but it takes 3-4 tries to strike a thawed mouse while I'm holding it just right with tweezers. He doesn't strike accurately at all. That being said, he loves people. He makes NO attempts to escape, and he will just hang out with you all night and makes no attempt to get away. I wouldn't recommend this method as a training tool, but he acts completely different before and after. You'd never know he was damaged goods until you saw him eat. You could hang out with him for 24 hours straight, and not see any problems.
The adult is now 20-25 years old, and still in perfect health, now 5 feet long. He doesn't mind being a lap snake, but if you leave him unattended for an hour or two he'll be gone again.