Boa constrictor escaped outside....

[Frantic]

I was a total idiot and forgot to close the window, and this is the night he decides to escape his enclosure. The windows in our house are old, and he just pushed the screen mesh out, so it seems the seal had given out.

He's a little under 5 feet, around 3 years old, so he's not small, but he won't get too much bigger either. When he curls up, he takes up no space at all, so it's not easy to find him.

What can I do to try to find him or lure him back?
There is a forest behind our back yard, and if he wanted to go far enough, he could easily have gone there, in which case it's a lost cause.
There's a drain pipe that runs along the front of our house which is close to the window, but I've checked with strong flashlights, and he doesn't seem to be inside it. I've blocked off the entrance with a cardboard tube for now. Although if he went far enough, the pipe bends and goes down where I can't see anything, and it's backed up with debris at the other end, so if he's in there, he would have to turn around to exit. I'm not sure if he could even turn around, but he seems agile enough.

There are bushes in front of that window, as well as along the side of our house, but the whole area is covered in pine needles, so he could be anywhere.. I poked and prodded along the roots and looked higher in the bushes.
Last place he could be would be under our slightly raised deck at the back of the house, but I could see pretty clearly with a flashlight and I still haven't seen him there. I suppose he could be well hidden in one of the slight ditches where the flashlight fails to illuminate the bottom...

I've set out a water bowl, tried putting out f/t rats at night (he ate 5 days before his escape so he's probably not hungry enough to seek them out yet), I have his hide with a heat mat set up from outside the window and have the window cracked open at night, with his enclosure near the window and ceramic heat emitter on, in case he seeks out heat and returns back.
I've also set up flour trails to see if he's travelled around here.
I'll try putting out rats in about a week again.

What else could I do to try to entice him to return? I can't look into neighbours' yards without permission, and people here would kill a snake if they saw one. I keep checking around my house every day.
Is there something else I could do to make him more compelled to return nearby? I've heard of using a minnow trap with a live rodent inside, but it seems cruel to leave the rodent trapped outside, and though I'd be willing to try it in desperation, I feel like my boa wouldn't even get all the way inside for the trap to work.

Honestly, I don't even know how far he would have wanted to go. I'm only guessing that he'd trace the walls and try to find a cosy retreat, but I wouldn't put it past him to be curious enough to get across an open field into the forest or a neighbour's yard.

I know this is my fault entirely and I'll regret this mistake for the rest of my life, but please if anybody could give constructive help, I'd really appreciate it.