Remember that escaped snakes rarely venture out into the open. They're more likely to travel along the baseboards and through concealed areas. That might help you to mentally map out the most likely path he took on his adventure.
My 4 foot carpet python got out once. Unfortunately for me, my heating vents are along the baseboards. I didn't think she'd be able to squeeze between the bars on the vents, being as big around as she is, but I was wrong! My boyfriend found her two days after the escape using a mirror and a flashlight. She had squeezed her way into the vent, somehow vertically climbed the inside of my wall and wrapped herself around the electrical box for my living room light switch. My boyfriend pulled out the box, capped off all the wires and I spent the rest of my day luring troublemaker out of the wall with a mouse.
I was so upset at the time, but in retrospect I have to give my snake respect for what she did. She squeezed through a space half her size and survived two days holed up inside of a wall. Never underestimate snakes!
Watch your cat and dog carefully. Even if neither are the hunting type, they will react to seeing a snake loose in the house. I might have lost my kingsnake forever if I hadn't turned around one night to see my cat obviously upset by something he saw on the floor.