I think so too. I wouldn't think he would make the effort or risk transporting her body that far. Much easier to dispose of it nearby and then transport the phone ( Or have someone else do it) to the other location. It makes sense that he would want authorities to think that she is somewhere in Idaho, while actually the body is nearby. He likely wanted it to look like she had been murdered while on the way to see relatives, and assumed that that's where they would look.My honest to God opinion is that she is somewhere close to home. I think his goal was to point them in the direction of southern Idaho, but I don't think that's where she actually is. Recall that his entire purpose is to make sure she stays hidden forever. So why would it matter where that is? If he has access to mines, etc. in CO that will likely conceal her forever, there is no need to move her across state lines and take the various risks that come with transport of a body. Instead, he just gets rid of the body close to home quickly, and then sets about making it look like she was in ID. No one has to actually find her there to make his story work, if it goes how he plans.
Again, just MOO so I could be way off, but I do think she's close to home.
Could be wrong, but that's what I'm thinking. Imo