I used about 21/2 gallons to winterize my last fiver at 39'. We now have our Fleetwood Expedition at 42'. We also have the washer we didn't have before and a fridge ice maker but have that line discon...
I haven't use the pink stuff in over 8 years. I just blow out all the lines. Don't forget the lines to the toilet. and the water in the bowl. Then drain the tanks. Good luck