BBM
I grew up on a hobby farm in rural Appalachia, and this has been my experience too, save one family in the area. They're all 'nice.' Their own daughter was about my age and we played together as children, the mother worked at the local store for many years and we'd always chat with her when we ran into her, very pleasant but very superficial interactions, the father was the most reclusive but would still be friendly enough the few times anyone ran into him (no one knows much about him). But the mother and now adult daughter have increasingly dropped out of sight over the years. The last time my mom saw them, she was driving home and passed them all taking a walk near their property and stopped to say hi. The mother and daughter immediately turned away and covered their ears until she drove off, while the father just chatted with her a bit like nothing was strange about this. My mom verbatim described them as 'very shy.' But something's wrong there, whether mental illness or CC/DV, extreme religious beliefs (their property has something of the look and feel of a cult compound), something else or a combination of things. Not enough to go on to call a welfare check or other services, no one's asked for help, and of everyone I know in that area the father is the one I could see pulling a Josie and shouting at them with a gun if someone actually ventured onto the property uninvited and asked if they were ok (in a community where everyone has firearms and everyone's homes are set back from easy public access). They're who the Oak Park Station family remind me of.
I share your suspicions. I love living in isolated areas for the privacy and freedom, but that same privacy they offer can be a draw for people with secrets to keep because it makes a huge difference not having neighbors close enough to overhear or see anything suspicious enough to get involved, interfere. I wonder how often Shannon makes it off the property on her own. The same long dusty roads that make it so unlikely that anyone could have arrived and abducted Gus without being noticed would also make it hard for someone to leave without being noticed. In the few recent images we have of her, she looks like she could be physically frail, which I think can lead to thinking she wouldn't be up to the manual labor out on the property (which she's likely been doing all of her life), but people similarly tend to stoop/hunch up like that when they're living life walking on eggshells, fearful, submissive. Josie meanwhile comes across as much more confident, squared off. I wonder if Jess was still kept on a tight leash (say, she risked losing her inheritance of her family property if she didn't 'follow the rules') when she was off with Josh, if the potential looming date of her moving out more completely onto property owned by Josh and more out of control was a point of contention (and could have contributed to the friction with Josh). Could even speak to a possible motive, if a motive enters into whatever happened to Gus. Jess could just be 'very shy,' maybe as a result of some mental health issues...but she could also be traumatized and afraid to speak to people. And wonder about some darker possibilities some of the (few) details could hint at, but this isn't the place. If any of this ends up being on the right track, it's just going to be twisting the knife in the victim(s) as their most painful secrets get dragged into public scrutiny.