I have lived in this area, not counting undergrad, for 17 years and this is a fairly new story that has been generated about Holcomb Woods. In reality, no bus full of children, Catholic or otherwise were killed in Holcomb Woods or anywhere else around here for that matter. That's the kind of thing that lodges itself in local history and would always be remembered. No one knows anything about a bus load of kids getting killed by the driver or by getting hit by a train which is another story I've heard about Holcomb.
Here's what I do know about Holcomb Woods... It's a big woods for around here since most of the area is agricultural in nature. The woods is owned by at least seven different land owners at last check. There is a public road that up until the last couple of years was unpaved that biects the woods. Kids from the local high schools have for years spent time on this road doing what high school and college kids do... hanging out, drinking, losing their virginity, smoking weed. It's not unbelieveable to think that kids over the years have added to stories about the woods and then passed them along to the next generations.
I DO remember one weird thing that happened out there that the sheriff was called in on. This happened at least ten years ago and I was working for a county agency. This is second hand information from a law enforcement officer who was on the scene. I consider it reliable and can probably be found in the written record of his logs from that time. The Sheriff was called to Holcomb Road to investigate a horse's head that was found alongside the road in the woods that was partially burned. The horse's head still had the halter on it and no one from the county had reported a missing horse.
I have also heard that some satanic activity has taken place in Holcomb Woods but have absolutely nothing to back up that story.