Most of my stands are placed inside the woods, the closest one i have to a field is 20yds inside the woods. I have never had much luck hunting a field edge or fence row. Try to pick a spot where several travel routs meet inside the woods to enter a field and set up, this could be 10yds in or 100yds in...the later the season becomes the farther back toward the bedding area you want to move to intercept the deer before light fades. Also bigger bucks are going to wait untill last light to enter a field and hang around where there is some other forage for them to eat inside the woods, acorns ect.