1972 alaskan truck camper

HI all, I'm new here, I bought a 1972 Alaskan Truck Camper 10' non-cabover, it fits in my 1994 Dodge 3500 CTD Dually. I am trying to start a restoration on it (slowly while still trying to use it during the warmer weather , the immediate needs are: 1-The furnace needs to be replaced - Has...