Not sure exactly where your condensation is, but I'm guess windows or on some walls. Caused by inside / outside temp difference, shower humidity, wet towels and gas heat. We full time as well, and recently added a 35 qt dehumidifier and have it set on 45%. WORLD of difference and no condensation in windows. No more muggy feeling in the camper either. Another thing to consider, is crack the cabinet / closet doors open, as you can get condensation in those areas as well. This allows the temp in the cabinets to be the same as the rest of the coach. In my first camper, it was so bad one time all my clothes in the closet were damp, as I had left the door closed.
As for heating, we use our roof air heat strips most of the time, or small tower heaters, one on each end of the fifth wheel. We stay away from the gas furnace as much as possible, and usually don't need it unless it gets well below freezing.
John and Rebecca Dickson
Emma-7 / Little John-5 / Iva-1
Full Timing Again, Rev B
2013 Ford F-350 Lariat CC LB PSD
2015 SOB TT - With OC's Awning Poles (#8)
At least in Heaven, RVs will be perfect, and I won't have to keep fixing them.