Late to the party but we had a Conqueror trailer, big (I think it was a Mombassa) tent with permanently attached annex. The screens for the annex zipped shut but not the bottom of the heavy canvas flaps. So always some air coming in at the bottom. Two medium triangle windows up top with one huge window.
I'd put the Buddy heater on a table downstairs in cold weather and open the two triangles about halfway. Created a bit of a chimney. At 15 degrees outside it was usually about 70 upstairs and 40 degrees downstairs with little to no condensation.
With other temps and situations, when/if condensation did happen and we were leaving before the sun could do its thing, I'd partially open the tent at home in the garage (ceiling prohibited full tent deployment) and blast it with fans for 3 days. Same for rainy last days. Never got any smelly growth.
The stock mattress was a lame foam thing covered in zebra-patterned cotton fabric. Got moist. I replaced it with a Cabella's queen sized foam/self-inflate hybrid thing that was covered in the traditional almost-textile plastic-ish stuff. 4" thick and absolutely luxurious. Never got damp too.
