I think if she had been planning to go hiking she would have wanted to take a shower before work. So if she left her house after 1:00, she would have been where the car was found at about 2. Maybe she planned on spending an hour and a half or so up in the mountains. You figure she would have wanted to be back at home at maybe 4:45 at the latest to shower, get ready and get to work about an hour later (that would be if she worked at the Commerce City Red Lobster which is closest to her house). If she was just driving around maybe she didn't plan to shower but if she went hiking I'm pretty sure she would have.
A coworker said she always arrived at work 15 minutes early, and with clothes freshly pressed. --So, that reduces the time just a bit. Thank you for your very insightful thoughts.