My bait pile is 350 yards from the spot I shoot from which I can approach w/o showing myself. Two coyotes were killed there last year and this winter not a single yote has shown up during daylight hours(I don't watch it full time but check 2-10 times a day). I know they can't see, hear, or smell me before I see them so most likely they've been coming to the bait only in the dark. I wouldn't set up a bait less than 250 yards from my shooting position and best case would be able to check it with binoculars from 400-500 yards before getting closer.
If I could afford it, I'd have a night vision scope on a dedicated night rifle.
Eliminating coyotes is not a one time deal-you'll have new animals every year.