I think it depends on the definition of "rage killing" (I cannot actually find one). To me, a rage killing could be as simple as getting angry enough to slap someone, they fall and hit their head on something hard and die. That is not, IMO, overkill or pretty violent, although violent enough. And that could happen anywhere: in a vehicle, outside of a vehicle, in a house, outside a house, at the side of the road, on a trail in the woods, next to a lake while fishing. So, if something like that happened to Dylan, his body could be in a lake, in the woods, off any road, etc and still there would be no HRD scent on a truck or in a house....respectfully snipped....
Ok, I didn't say anything about anyone exaggerating. I'm trying to hop on the bus and see how things went down according to others. So, let's get back to MR as having a violent temper. Rage killings, IMO, are usually pretty violent, no? Overkill? Someone mentioned earlier about MR having about 18 hours to cover up his crime. So, let's say he violently murdered Dylan at his house or outside the house. He's got 18 hours to clean up his mess. Does he drive Dylan's body as far as he can and still get back in time to make his errands? Doe he dump Dylan's body in the lake? Does he dig a shallow grave?
I think the lake is almost ruled out. If MR transported Dylan's dead body somewhere, then surely there would be hits on the truck, I would think anyway.
I'm rambling again.
I am not saying any of that happened. Only that the above are some of many possibilities of what COULD have happened, and should not be ruled out unless proven impossible.