I have decided to winterize with the antifreeze only method, including placing it into the fresh water tank on my 400 (I know this is somewhat controversial).
My question is around the Alde - I have drained it using the yellow "tab" valves, and set it to bypass before introducing antifreeze. Then I ran all faucets until I saw pink, emptied the black and gray tanks, poured some more antifreeze down the drains and a bit more down the toilet. Lastly opened the fresh water drain until I saw pink, and did the same with the two water line valves near the Alde. That all I need to do? Surely some small amount of water remains in the Alde, is that OK?