I'm of the opinion RA knew the lay of that ground like it was his own. I think he'd been all over those woods, that bottom land, along the creek....probably hunting it, fishing, etc. I don't find it in any way curious that the CS is where it is.
I'd even wager there's a good chance that the woods had several established trails down in that bottom land, where folks would reach the creek from the bridge. I imagine all sorts of activity in that area over the years....smokin' weed, drinkin', campin' overnight, fishing, hunting, etc.
I've studied photos of the area, of the crime scene, video's of the cemetery, the old quarry there on the hill, the path down the hill from that side....etc. etc. It's a typical wooded area along a stream, nothing more, nothing less.
Depressions aren't unusual in those areas, the course of the stream changes over years, and/or flooding carves out channels here and there, washout from high water, all sorts of stuff.
I'd expect testimony involving the exact path the girls and the killer took from the end of the bridge to the crime scene, very likely including evidence of movement through the woods, disturbed ground, possible foot prints, maybe even photo proof of exactly where they crossed the creek and where they went up the bank on the other side. It really wouldn't be terribly difficult to track/discover where that happened. I wouldn't be surprised to see boot/shoe prints brought in to testimony.
I think BG/RA marched them down the hill, across the driveway, down another small hill, across an already established trail to the creeks edge, across the creek at a shallow point, up the other side, a short distance thereafter, all familiar territory to him, and murdered them right there. I see no evidence of any sinister planning for a ritualistic murder in broad daylight by either BG/RA or anyone else for that matter. Simple. Keepin' it simple here.
He then in haste tried to cover 'em up, and fled up the hill using the woods as detection protection, ultimately out on to the road, jumped in his car and drove away.
Sure, I see the timeline as being important, but I also think a whole host of other evidence will be presented, some unknown to the public at this time.