We can argue that RA was trying to avoid surveillance cameras, but he missed the most obvious ones in the entire area on HH. We could see them plain as day from photos on Google maps right after the murders, so I don't personally think cameras crossed his mind, at least not on the way there. JMO.
We can argue that it isn't uncommon to back into parking spaces, but imo, there was maybe more to the way he'd parked that drew attention. It was significant enough for at least two people to notice it, report it, and LE to include it in the PCA. JMO.
We can argue that it's normal to carry a gun and knife, but if what we see in his pocket really is the gun, then that is not the normal way to carry, imo. And considering both were used in the commission of a violent crime, I'm not going to give him the benefit of doubt. JMO.
We can argue he was just out hiking that day, and was triggered, but he parked concealed-like, was carrying weapons, was described as walking with purpose, head down, unresponsive, and "grumpy," made it to the bridge in probably 15 minutes, then waited there for over 20 minutes. JMO.
I mean, in my view, his behavior was suspicious from the very beginning, when he parked. We can argue all these things, but in the end, he did not just go for a hike that day, he killed two girls (allegedly). To imagine he did all these things and then just happened to be triggered, or that he had just wanted to kill someone randomly near the MHB seems a farther stretch than him knowing the girls were going to be there, even if only knowing that an hour before they left. JMO.
ETA: in regards to the white spots being A's shoes:
We know the video is only 43 seconds, that's not enough time for A to be behind him, pass him, get ahead of him, and still discuss him with L as he approached, IMO. And if for some reason her shoes were off and sitting on the bridge, he walked right past them, they all went down the hill, and he emerged muddy and bloody along 300. If her shoes were on the bridge, wouldn't KG have seen them when she crossed the bridge that night, looking for the girls? The shoes weren't missing, according to the PCA (only underwear and a sock were not recovered). And I don't think LE superimposed BG over a video of A on the bridge, either. Why would they do that? I just can't find any way possible for the white spots to be A's shoes. JMO.