Yes, I think you are exactly right. I'm not discounting any of the witnesses, and I can make it work.
They leave at 12:11-ish on a mission to meet their "friend." They ride down Evans, turn and ride by Mr. Carpenter's house, then pass the sewage lift station driveway on Arbutus where the perp is hiding. He sees them, so he walks out the other end (Maiden Lane, and along the fence). He is there waiting when the girls approach. He strikes up a conversation and lures them into the woods. TG comes along and swerves to miss their bikes, on the blind curve, as he described it, which is NOT the gate.
The perp subdues the girls in his vehicle in the woods (handcuffs, chloroform, whatever), then realizes that the bikes left where they are will point LE in the direction of the woods. He wants to put a little distance between the abduction location and the bikes. So he walks them down to the gate. There is no risk of being seen from the other side of the lake, because this section is obscured. If someone comes along, he will just smile and say, "hey, my daughter left her bike here," and nobody would ever suspect an abduction!! He thinks leaving them at the gate will make it look like the girls went into the lake and buy him time, which it does!
He returns to the car, and drives away.
LE denies the existence of TG (three times) because they don't want to reveal to the perp that they know the bikes were moved.
This has to be just killing TG that he was within feet of the girls and could have saved them, if he had only known.