The Syfy Network has a great video of this location and the Cylon Base: Location, Location, Location.
We passed Riverview Hospital on our way to the Breeder's Canyon site in Coquitlam. Traffic can be bad here, so we'd suggest going on a weekday. This location used to be a mental institution and is now used exclusively for filming. A security vehicle drove the grounds when we were there. We didn't make any effort to hide what we were doing, and the driver simply smiled and waved at us as he drove by.