I bought some 1” hose barbs and deleted the rear heater. I kept the heater hose loop to the dash heat and windshield defroster. The 2-1” hoses prob run back under your bus behind the drivers seat. Prob to a heater up front. This was the advise I got couple yrs ago around here. Defrost is good!
“Once in a while you get shown the light in the strangest of places if you look at it right.” -Robert Hunter