I've had many Kings across the years. At least 4 species.
(Forgive me. I don't have pets. I have animal companions. They are not kept in cages. They are kept in their "rooms", vivariums. You should see the photos of my 60-gallon Mojave Desert setup! At least 4 major hide spots, plus much more. I have even maintained lichen colonies on the rock that I got from the Sawtooth Mountains in ID from 1993.)
I made it a point with all my snakes, even Boas and Gophers, to handle them often - almost daily when not in pre-shed.
I have a track record with all hatchlings; they stop musking within the first week. I talk to them, handle gently, live feed, massage them at times, and communicate tactilly - the only way they understand.
One charmed Cal King who was lost twice was found within 30 minutes after I called out for him - both times!!
If we are squeamish & timid with them, they sense this (like horses or dogs). Let them know who is boss, that they are not in danger, and that you treat them gently, and they respond appropriately.
My current, desert phase Cal King is a gem. He was active for over 3 hours when home his first night. Of course, it helps when his home is a 60-gallon vivarium replica of the Mojave Desert.
They are ALWAYS more active in their rooms right after I handle. They love to explore my couch and towel closet (when I clean his room). Twice I've had him out on grass in the sunshine across the street.
Many people make the mistake of sparse setup, seldom handling, and treating them like a living jewel that seldom moves. They respond accordingly.
Caveat: There will ALWAYS be exceptions to the rule. I knew of one person who had a Mexican Black, known for docility, that would strike at anything that entered the room. It had to be exchanged for a better specimen eventually.
Every now & then a snake will be found that just likes to be left alone. The other 99% love to be handled, once you've earned their trust and understand their needs.