Proposed Canon
It is located in a mall near a food court.
Depending on the specific temporal mechanics involved, Parson may not have a job to return to. The conversation he was participating in when he disappeared continued without him, so time is probably passing while Parson is in Erfworld. If time passes at the same rate in both worlds, then Parson has been absent without leave for more than a week, which would be a firing offense; though his disappearance would be noted at the criminal level as well, which may defray the problem somewhat. There may be a time dilation, allowing him to return minutes after his disappearance, or millenia, but his absence from his home world is at least a few seconds.