I visited Centralia several years ago, and it was fascinating. I don't recall pedestrian access being impeded at the time, but there was definitely gas and smoke rising from a few spots around town. I happened to visit on a cloudy morning, and it had an eerie, ethereal feel to it.

There were several areas where the road was damaged, and it was clear that it wouldn't be wise to put too much weight over top, but there are still people living in the area.