well, im new here, but i've had lots of experience with lost snakes. when my snake has gotten in the recliner, i just wait it out. it has never stayed in there very long. if one of the snakes has been gone for a week or more, they will usually head for water, or basically the bathroom. the last time i lost my snake, it was in the bathroom about a week later. I wouldn't be worried about the snake dying in the couch because it will come out when it hungery. If you are no longer sure it is the couch, i would seal off the vents. One time my snake got in the vent and i had to turn the air way up to get it to come out. last summer my sister's baby milk was gone for about six weeks and i found it in my shower. they can go pretty long without food, so i wouldn't be to worried yet. And don't feet too bad about losing it right after you got it. My candy cane corn got in the printer a couple days after i got it.
I put the printer into a cooler and the next moring i found it!!! Good luck!