I'm still of the opinion that she may be still be alive. It seems to me that his intent was not for a simple, fast kill, but had intended instead to take her away to a hidden site, and to keep her for his pleasure, and could envision camping out with her for a large piece of time, in a shack or a hunting cabin his family owned.
I believe the site will not be too close to the areas that they are searching and they are, at this time, settled in well.
He'll need to come out to get food and supplies, probably tying and gagging her,and he may even appear in town at the various service stores for provisions. Furthermore, he may join in with rescue work, maybe hang back and just listen along the edges for any information.
I feel this is a crime of passion and lust and obsession, one that has been well thought out.
They could be many miles away, according to this theory, in an area off the Radar, and may not be found for some time to come.
There will be a slip-up in time, and they will be found, of that I truly believe. I can only hope that the find will be a timely one, one which produces a live and relieved, Holly.
I believe, as others have stated before, that he is in charge at all times, and that he would not have allowed her to carry her possessions. He separated her from them in the car (?), and at some time planted them around. I would think there could be evidence of his fingerprints or some DNA on her items unless he was smart enough to wear rubber gloves.