According to the flyer her sister posts at 56:33, Jenny is driving to the "musikfestival in North Dakota" on "new road 66". The hotel owner says it actually now on old road 66. At 58:25 there is a road sign shown outside the hotel that clearly says Road 15. Also, it's obvious this movie is not shot anywhere near North Dakota since all of the signs, cars and truck are European.
When Jenny comes to David terrified after seeing someone taking a photo of her, he says it was impossible for anyone to be in the hotel because he locked all the doors. Jenny says she went out to her car and left the door open to come back. Again a few minutes later as they go to her room, again David asks if she was too drunk or dreaming, because the doors were all locked and no one could have come in.