I noticed something about the show. In Episode 2, everything in the hotel is normal until the moment the mayor gets on the phone with >!Ruth!< . From that point forward, even while still on the phone with her, is when mysterious things start to happen to Loftis in the hotel.
So I went back and rewatched the other episodes. In Episode 1 she is the last character to speak before Loftis talks to the Sheriff to find out Shep is missing. In Episode 3, the last person in the office that Loftis speaks to before it cuts to that night (where things go downhill) is also her. In Episode 4, she’s the person who points out to Patricia that the woman who hates Patricia and her friends just walked in, and right about then is when the bachelorette party walks in and the party takes off. Finally in Episode 5, she’s the last person in the office who talks to Loftis before it cuts to him going to the Priest’s office and finding the mysterious messages and the mushrooms.
Edit: I also want to add that the only time Ruth appears in Episode 4 "Beach Reads" is at the Salty Whale starting when Patricia is setting the place up until Ruth points out the people arriving. The next time the camera cuts back to the bar where she was sitting, she's no longer there. We don't see here again for the rest of the episode.