Don't worry, I found her. Many thanks to this group and all of the similar posts that informed my search and led to me finding her in about 5 minutes all of about 3 feet away from her enclosure I'm not sure how long she was out, she was cold but not freezing, lively and moving around and such so I'm not worried about any ill effects.
This is both frustrating and embarrassing. I know exactly how she got out, there is a gap in the door of her enclosure that she often uses to sneak into a sort of inner cavity of the enclosure, but has never actually made it out before. Remedying the problem has long been on the back of my mind, but she hasn't utilized her little escape route in a long time so I thought perhaps she's gotten it out of her system – obviously I was wrong.
But now I have a question: I was going to feed her today, already have the mouse thawed and everything – do you think I should? I don't know if she is stressed out or too cold or what? She seems completely fine in terms of long-term health, but do you think feeding her in about an hour would be able advised??