PLEASE HEAR ME OUT and don't discard this as a possibility, also read the whole post before jumping to conclusions! This is Websleuths after all and I just want justice for Abby and Libby... more than anything.
I don't think that it's just a mere coincidence that their bodies were found on this person's property and he wasn't home the day they went missing (I am not saying he is the suspect but perhaps a relative of his). I'm happy for all the billboards in all 46 states and all but BG is definitely from the area. He was comfortable enough to kill 2 girls in broad daylight because he knew it was desolate, no one would hear/see anything, he also took them to another area (he knows this place very well). Since property owner wasn't home, maybe a cousin or friend went to 'house sit' or feed his pets, etc and decided to take a hike and saw the girls. He left them on that property and walked up to the home, showered, cleaned himself, changed (since no one was home, no one saw him cleaning himself or anything suspicious) and then he left. In the interview given by this man he is also wearing a camo hat (relevant to those who think BG is wearing a hat), a blue jacket, 'dad' jeans, so this just tells that he associates with people that dress similarly. Again, I AM NOT SAYING that this man has anything to do with it, but perhaps a relative, friend, cousin... etc. He is very old too and sometimes old people forget or aren't mindful of small details so maybe he hasn't been able to help with any information but I am sure something weird is going on here. My gut instinct just tells me so. Most of the time people expand too far or think too hard and the answer was right under their noses the whole time. Maybe the answer is just right in front of us, maybe this is why the suspect hasn't been caught yet because the search is so broad. I believe he is hiding in plain view; no one has noticed or would think that he would do that. Or he's a loner and not a lot of people know him.
lol