snow is a definite eye opener. I've seen yotes eat corn in the field but majority of them were mangey and sickly. As for edges here they stay just out of shotgun range! I find those wide open travel corridors to be hot locations. Its pretty open ag country in my area! A few sections I trap don't have any edges unless you consider a two track a edge. There so open rabbits have to pack brush to hide! Distance from edges has got to be a regional thing

What you observed is the coyote comfort zone. Their natural caution is the distance they prefer in the open as you would. If there was food close to the cover, they would be hunting it. That is not to say that coyotes will not plow through walls of corn , weeds, brush or trees. They use cover to conceal themselves from other predators, including you. You have to get into the coyotes mind in what it is doing and why. They prefer grassland and open spaces, but they are still experts at knowing exactly in the open, where the rise is which will hide or protect them from you with a rifle.
Snow is a great teacher, but so is dry dirt and mud, in noting where they move, and that includes going for walks on rural roads. I have been watching a family group play on the road here. They look spooked deer in the tracks tearing things up, but they are just screwing around playing.

will add that i made the mistake of gradually moving out into the fields further and further to avoid incidentals--in my mind--and actually moved myself away from the canines also.i'm an over thinker.

learned more from snow than all other things combined.

Coyotes are edge critters sure they go Into cover to hunt but they are like a good bird dog they use their noses and eyes to seek out game.
The last few years I have been placing large baits like a whole deer carcass about 30 yards from cover. Guess what my catch ratio has gone up dramatically. And that goes for dirt. sets and using CRs. Scent posts and flat sets before snow. And once we have snow find a track or tracks and hang a CR when the coyotes comes out of the near by cover.
A fire blackened chunk of wood placed about 15 yards from cover will get a canines attention even if the wind Is wrong.

If your not catching non targets like fox,coon and opossum your missing coyotes.. The set that doesn't have a coyote in it becomes the backup set for the next one.