All Dump valves on this and most Class C do not have either Gray or Black in a heated Basement. The "Campin Cozy" package does have 12V heater Pads on both Gray and Black Tanks. Fresh water is interior under the Bed so it is in heated area.
I am speaking about a 2012 now With "Campin Cozy" package so 2015s may have some change here. MY
Gray and Black have TWO valves on each. One at the tank to keep the tubing empty of Liquids. The second is closer to the outlet so in warmer weather where you may close then open each day to empty they are easy to reach. The two located at the tanks are more of a reach especially the Gray Tank. Could easily add valves with cables so the handles were mounted by access door if you wanted them handier. Mine is a 2012 but only change I've noticed looking at newer units is a change to Gray Tank (by eliminating Spare tire well which is below floor in the rear storage on mine) making the dump tube a little higher from road service than mine. (My Gray tank is somewhat lower than the 2015s I've looked at.)
Have cold weather camped below freezing several times with NO issues except I have never purchased a heated hose so always had to disconnect and drain hose to prevent frozen water hose problems that I saw other campers having. Double pane windows are great compared to past trailer with single pain. Do not have the condensation issues I had with trailer. Have enjoyed ours with exception of missing my past Diesel truck for in the mountains. V10 does well even with a Towed but still is not a Turbocharged Diesel. Would like to switch back to Truck & Trailer this or next year.
Not sure if I helped at all since there is always changes possible each model year.