If you want to go the easy redneck way:
1. A five gallon paint bucket.
2. Put bait inside on bottom of bucket.
3. Place bucket near a piece of furniture or something that they can climb onto to get into bucket.
4. They can never get out.
Albiet now you have to deal with live mice, but I have caught a plethora of mice in record time with this method out in my barn. I just slap the lid on and they enter the mice relocation program down the road into a field.
To the OP they will come out of the duct work for food placed anywhere. I'd just put a ladder near one of the vents with either a mouse trap or the bucket trap on top of the ladder for a day or so. They'll come out for it.