After you checked with your friend I hope you called the cops. Give description, probably some of the neighbours had the same experience, they should be asked and warned of this person. And if you had a glimpse of what he made notes of, you will be a great help.

Sounds like a scout for a robbery. I mean, why would he look at bedroom when he is there for the toilet. In most apartments/houses the bathroom door is different, so it sticks out when you first see it. No way he was just confused where he was going, especially if he is maintainence