I think he tossed the knife in the Snake River, if he disposed of it near Clarkston. Scrap metal company too risky.
He had to dispose of his clothes, shoes, knife, mask and any plastic that he used to protect his car from blood, possibly even seat covers.
If he had not planned in advanced with bags to contain these items, then I'll look at this crime differently.
It's possible he took a nap. But he certainly was turning off his phone for the evidence disposal, IMO. Several different bodies of water would be possible. He would have needed something to weight his bags, though, and the bags would need to be sturdy as clothing items might get loose and then be found.
It almost sounds as if he drove home the first time while perhaps disposing of *some* evidence, then went home, cleaned up, went back out again around 9 am, and then made the same circuit and disposed of more evidence (perhaps some items from home?)
Whatever the case, I'm finding it hard to believe that he didn't leave blood evidence of some kind in his car or in his home (if he showered there).
There are showers at an RV Park just steps from Kate's Cup of Joe, but I seriously doubt he was brazen enough to go use them (most places make you show ID and pay for a shower, for safety reasons, but who knows about this one).