My thoughts on this, as I've had it happen to me. Crickets as bait will not work, as they are not a natural food for corn snakes. At least I've never heard of one eating them.
Corns are escape artists. My cats helped break mine out once when I was in college. It took a few days, but they turned up. Look in warm places (water heater, furnace area, under the fridge, under the oven, around heating resisters) and keep your eyes open. You never know when you'll see part of them.
Having a food item as bait isn't a bad idea. Do you feed live or prekilled? If it is prekilled, it may be easier. Put the prey item in a container that has a small hole in it, just big enough for the snake to get into. Assuming it is hungry and will eat the prey item, if the hole is the right size, it will not be able to get out after it eats the food left for it.
And corn snakes are actually diurnal, not nocturnal. Just an fyi there.
here's a couple pics of mine:
