Check under the kitchen and other cabinets that are set on the floor. Often the wood frame below the doors has a hole in it which doesn't lead to the cabinets but to the wall. A couple of strips of duck tape will close those holes and keep kitten safe.
Check behind the plumbing, under bath sinks and around the hot water heater.
Check behind the plumbing, under bath sinks and around the hot water heater.