I think fire would be right up there with vehicles, although I lean more toward a vehicular accident. Something I questioned very early in this case was the dogs going from the site to the reservoir. I think it's possible that the truck was washed at the reservoir. If he was run over, his scent would have been on the tires. If the path to the water was gravel instead of dirt or grass there might not have been evidence of the truck being driven there.
I keep thinking of Sheriff Bowerman leaning toward "an intentional homicide." Those are really really strong words.
I also think if an accident happened, someone would have come forward by now. Surely LE has "offered" them this route and warned them to come clean saying they might serve a little time or none at all, opposed to LE finding Deorr's body themselves and pressing who knows what charges against them.
It's hard for me to envision that they killed him "on purpose." I think if Vernal snapped he did so with no forethought. Also, if they wanted to rid themselves of their young son, they could've done so in a way that looked like an accident with no suspicion (horrible thought, but say, if they "helped" Deorr into the reservoir, or they left him far away on the mountain to fend for himself, knowing searchers wouldn't look that far, or by the time they did Deorr would be deceased, overcome by the elements or victim of an animal attack. And, not to sound like a broken record, if there was an accident, they must have a REALLY DAMN GOOD reason to cover it up. Like some have surmised, to cover it up so LE doesn't find out about drug use or other irresponsible and/or illegal behavior that contributed to Deorr's death. And, as I've always said, I think if it was an accident, they may have covered it up so their families and friends and the whole wide world would not be privy to signs of ongoing prior abuse (just a theory of mine, and if/when they find the body it'll probably be late to determine that by now anyway. I do wonder how Deorr was "disciplined" and if anyone ever witnessed any abuse).
It's pretty dang near impossible to speculate about ANYTHING because we have so few facts to go on. We know they've lied and continued to lie even about things that presumably people don't lie about (who made breakfast or what they ate, for instance). And most of all, it's almost a moot point to theorize a lot of what we do in this case because Deorr may never have been on the mountain! All we can do is hope and trust that LE and Klein DO have evidence and that more will be found, and that someone comes forward with information. I pray every day for this to happen.
Until then, yes, I too will continue to speculate, wonder, ponder, theorize, brainstorm, suspect, etc. I want this case solved and justice served, and it makes me ill to think it may never be.