Without any major developments in this case, my thoughts haven't changed. There's a strong possibility that Jane disturbed a transient who was hiding out in the ladies' restroom. They could have been using the restroom to get high and had a psychotic episode when Jane walked in, then fled the scene before the boys knew anything. The only alternative is that someone was lurking in a remote restroom on the off-chance that a potential victim happened to stop by, which seems unlikely.
I still don't rule out McGawley. What are the odds of a bloody hitchhiker being picked up half-a-mile from the murder site? McGawley had been fighting with his wife and may have taken his anger out on Jane.