Here's my theory. I used to believe the morning abduction theory, but recently changed my mind. I can't get around the phones not pinging after 2240.
After hanging up with Rob, she decides to take a bath. Had a long day, wanted to relax. She puts on fresh underwear and t shirt. Someone knocked at the door. Through the peephole, she sees someone she knows well. She puts on shorts or sweats. Perhaps, they had been at a bar down the street? He says he can't drive, asks for a ride home. Earlier, she had put Travis phone in her purse, so she wouldn't forget it the next day. (I know they found a purse, but I know no women who only own or use one purse. Most of us have several.) She grabs her phone and keys and puts them in her purse as well, slides on flip flops. Her heels are in her briefcase, which she had left in the car, she had a lot to carry earlier. They leave to give him a ride home. From here, I believe something happened after they left the apartment. This part of the story is pure speculation, no evidence of where they went at all. But in the end, he does something terrible. Since he knows the family, he knows they're already looking. Needs to get the car away from the crime scene, her house, and his house. He dumps it in a high crime area, hoping it'll be broken into or stolen. This is the only logical theory that I could think of that fits what we know. Of course, it could've been a coworker to stop by and ask for a ride, I guess. But would she help him? Idk.