BG knew not only the park, but the possible LE response to his heinous crimes.
That's my brass tacks assessment. He's done it before, and it scares me to state this, most likely (come on, people) watched the same YouTube videos to perpetrate this crime.
We've pieced together various scenarios here on WS. Members here stated stuff which indicated they thought this guy is some dumb *advertiser censored* who has spent his entire work career picking up scrap lumber at work sites, and "just happened upon" the incredibly hidden Monon High Bridge adjacent to Delphi, Indiana.rs.
Who the heck even knows where Delphi is located? There are people in that community who clearly do not know how to access the trail which leads to the Monon High Bridge, over Deer Creek. Who would know where it's located, and/or why?
I disagree as there is a very plausible alternative. For example: BG has never committed murder and is simply pre-disposed to commit a horrendous crime. BG then picks a place where he feels comfortable.
The hiking trail is neither the
Statue of Liberty nor the
Lost Dutchman Mine in regards to recognition / obscurity. BG knows about the trail either by hiking, messing around on it when he was younger, heard about it from a co-worker, saw a sign for the trail while driving one day and was bored etc.
As you mentioned, BG does know the park well, but this could have been gained over the course of a few relatively long visits, being somewhat observant and willing to try new trails for an hour or so. He has not demonstrated, say intimate knowledge of the climbing routes on El Capitan or winter routes up Mount Rainier.
As for the crime, it is entirely possible that rather than being a "pro", BG was just impulsive and got lucky. For example:
He sees the potential victims and he pre-disposed to commit the crime. He looks around and does not see any readily apparent witnesses. BG then tosses out a ruse- he has nothing to lose from attempting it as he has not committed a crime yet. The ruse does not need alot of background knowledge, acting or a uniform (say, Park Ranger). BG uses something from his own general experience:
"I work for the rail road. You are trespassing on the bridge. If you take the bridge back, I"ll need to call the police. Don't worry, I"ll show you a ..."
If the victims hesitated, started to call somebody, looked like they would shout, BG just breaks off the attempt (
"OK, you can take the bridge back, I"ll just give a warning this time").
As for intelligence, BG's intelligence could be high, average or low. He could be an intelligent, but anti social guy who is a self employed mechanic and acted on impulse. He could also be an overall but not totally dim witted scrap collector who took a moderate chance and got "lucky".