Clearly labeled mandos on 8,11, and 13, spray-painted arrows on tree trunks.
The creek is OB, pedestrian paths are not, however always wait for non-golfers to clear the hole if present before throwing.
All private, fenced-off backyards are OB. DO NOT JUMP FENCES TO RETRIEVE DISCS! Walk around to the front and knock on the appropriate front door, then ask politely. Most people are nice and are happy to help you retrieve your disc; others may not be home, or will refuse to help. It is their choice, and they have no obligation to help you if they choose not to. It sucks, but it is not an excuse to hop the fence, which would be trespassing, in which case the police can and will be called. It is easier to just write off your disc as lost in this case.