I think that maybe, he shut his phone down before heading to the Salida worksite or possibly left it at home. He could have put her into one of those heavy duty industrial strength green Glad garbage bags, I’m sure he has them. Heck, I can fit into one of them! Then, put her in the back of the truck. Those bags are mighty strong and if he worked quickly no scent left behind. Quickly dropped her in a preplanned hiding spot until he was done in Salida. Once he had what he needed from the worksite he went off to make the evidence disappear. Under cover of darkness, I’m thinking the personal item that was found may have fallen or blown out of the truck and it went unnoticed until found days later, just like that board that TS had to explain with Gannon’s blood on it. When all is done, he goes home to clean up any obvious mess that may have happened in the house, loads up the bike and shot puts it into the ravine and then leaves for Denver or somewhere close, putting him at a great distance from the crime scene (the house) and disposal site. And as a late friend would often say, “That’s it, and Bob’s your uncle.” Except in this case Bob’s the “cat.” 
All MOO!

All MOO!