You can heat the MH after winterizing the potable water. The boiler antifreeze is on entirely separate circuit than potable water. I should mention that proper winterization of the Aqua- Hot means running pink RV antifreeze through the hot water side until you get pink stuff from the faucets. Blowing them out with air will not get all the water in the potable water boiler loop. As I recall it took about 5-7 gallons of pink stuff to winterize my Dynasty. Don't forget the washer/dryer and its P trap. The Ice-maker, too.
Jim and Jennie, Cats=Bittles and Potter, 2000 Dynasty 350 ISC
2013 Silverado 4x4 Towed with R1200GS in bed.
PROV23:4 Do not wear yourself out to get rich; have the wisdom to show restraint.