I don't have a link, but IIRC, there was an article or video saying the bikes were headed west.
I'm a little surprised no one or the biker didn't stop to check things out. I would, especially if I knew the trail and where the gate was. It would be strange in such a desolute area of the trail, two children's bikes and them not around.....and a gate to the lakeside. Not to mention the high fences to confine the area even more, kwim? It not like it was open trail and kids threw the bikes down to explore an open area.
Upthread, someone posted the video from Big and Tall (presumably) outside camera and it shows the girls heading away from the area. I don't know where the camera is in relation to the road leading to the lake, but perhaps someone local could watch it and tell us if they were heading towards the lake or the opposite way? thanks.