Alright, I've done a few runs in the asylum this year, the most recent being on 10/1/2016. I have come to discover that the police do not patrol inside the buildings, they stick to the roads outside (I dunno, maybe they're scared about ghosts??).
ALSO: The patrols are few and far between, you should be able to skate by pretty easily.

HOWEVER: I do have one warning, if they see you, they will pursue, I haven't gotten caught yet, but I know someone who got nailed. Apparently they will search the surrounding area for about an hour before giving up.