I support JLC's ideas.

My sis had a pet lizard(egyptian sand fish?) go missing from it's feeding tank. We would feed it in a tank with no substrate so it wouldn't eat sand-covered crickets. No one realized it had gone missing until we saw the cat playing with something. Turned out to be in the process of deciding whether or not to make the lizard its meal. Luckily we saw it happening in time to get the lizard away. It was tuckered out and stressed to hell, but luckily the cat didn't bite it or scratch it(declawed in the front, I wonder if that helped) and went on to live another 5 or 6 years.

Watch the cats for a day or two, and if you can't watch them, sequester them in an unlikely place for the snake to show up. Possibly do this for the dogs too. I've come across at least two posts on these forums in the past day or so about people finding snakes that have been missing for a long time, and while I hope you find yours alive and well those chances decrease dramatically with other pets roaming around, especially cats that you can't always watch.

good luck!