Our "Q" is in the shop having the pull cables for the black and grey tanks rerouted so they will work properly without binding.
When we went by today to see how it was going we found they had it up on a lift to access everything. I couldn't resist taking a couple photos and looking around underneath to see where everything is located.
This photo was taken from the drivers side rear corner. The Red and Blue low point drains are in the right hand corner. The fresh water drain is the white tube in the center of the photo close to the hitch. All of them are fairly easy to access when winterizing.
Low point and Fresh Water Drains
Hopefully this photo will help other "Q" owners locate the drains on their unit.