Funny, (not funny), I was just going to say, "wow, they were really close to the house, weren't they?" That's less than a quarter of a mile. I think a lot of how we all feel about children missing in the wilderness has to do with our personal experience in the woods. I personally looked at that distance and felt it was totally within reason that he may have headed toward the road. Again, hoping they check every inch of the roadside on the way to his parents' home, if what we think is true about where the parents live in relation to the point of where he went missing.
I had the same reaction. Not far in the woods at all, shorter than the distance from my house to the mailbox. I live on 100 acres in the woods. From pictures of the search it looks like the paths are pretty w ide and open. I could definitely see him heading back to the house and up the road.
When my kids were that age and we would take them hiking we'd usually plan/expect about 5 miles in two hours. They had no problem covering that distance.