Any kind of outside blanket cover on the tents equalizes the surface temperature and minimizes/eliminates condensation. After experimenting with vinyl tarps and shipping blankets, I settled on quilted king size bed throws. I reinforced the corners with iron-on patches before adding grommets. I added extra "army hats" purchased from my local RV dealer and use bungee loops to attach to the camper. If it's windy, I use small spring clamps to stabilize the loose ends.
I was looking into Hypervents-its a pad that you place under your mattress and people use it on boats. Search for marine vented mattress. There are also air vented mattress pads that go on top that circulate air through.
Hello, we have tested the Hypervent material, it works to keep your mattress dry, however we still found condensation on the bunk door under hypervent. Just can’t get enough airflow under the mattress to heat up the bunk door above the due point. Good Luck
We use something made for protecting car seats from large dogs. So it is an impermeable pad with a faux woolly top, and that makes it comfortable to sleep on. I just have a cotton jersey sheet over it now. Flannel might work too. And one can also lay a wool blanket over it, between the sheet and pad, for an extra moisture absorbing and insulating layer for winter camping. Works great! Editing to add that it goes under the majority of our body and it is washable.