'Tis the season. There will be an instant replay for those who are getting out for the first time in the cool, damp spring weather. Either the space blankets from Cabela's or similar or the Pop Up Gizmos will go a long way toward fixing this. Note I didn't say WILL fix it. We also bought a product used in boating applications called HyperVent. Sworn to remedy the problem. Not quite, but what it did do was elevate the mattress about 1" above the deck so that it didn't get damp. Some folks swear that if you slightly open a window, problem solved. DH wouldn't even think of opening a window when it's cold outside and he's trying to get it warm inside, so no big news to report there. We did use the fan only on the furnace and it helped, but an oscillating fan sitting on the table will likely accomplish the same thing. Some folks have never had a single problem. Others swear that they're about to drown. My strictly unscientific study has shown that what works for one won't work for another. Trial and error. One thing you can do to help considerably is to make sure you don't do things like boiling water or heating where you have steam in the evenings - be sure to run your stove venthood for a good long time. We never had moisture dripping from the top, but in spite of all, we did check under the mattress & HyperVent every morning and just wipe it with a towel if needed. If it was more moist than usual, we'd stick a couple of tall cans or similar to hold up the mattress until you were sure it's dry. One 99% guarantee is that if the pillow slips against the end of the canvas area, the moisture will wick and the pillow will get damp. All this is just part of the charm of hybrid camping and you'll figure out what works for you and what doesn't, but moisture is a stinker and you'll just have to work on it. The greater difference in the inside and outside temps is one of the culprits. Meanwhile, just enjoy!