Like sweat on a cold aluminum can on a hot day, the same thing causes condensation inside our campers. The only thing that can slow down the effect of condensation is for evaporation to happen as fast as condensation occurs. That requires air exchange: old air "out", new air "in."
If it's that bad that water actual puddles in the bottom of the window, then first, crack a window near the window if it does not open. And second create air movement across that window .... a fan.
We keep the ceiling fan turn on, pretty much all the time, especially in cold weather for this very purpose. But, we also have a front living room model fifth wheel and there is no closed wall between the upper level living room and the lower level kitchen. So the ceiling fan in the mid-kitchen creates good air circulation in both sections of the camper.
Our bedroom, which is in the rear, because its an enclosed area gets way too warm. Somehow heat gets trapped in there when the rest of the camper is comfortable. I really think it's because of the ceiling fan. It doesn't circulate in the bedroom.
We have had small clip on fans since our first pop-up camper. We keep them running and the condensation in the bedroom windows disappear.
We now have 3 of these fans in the camper. One in the front living room sitting beside the television which moves from the top of the television to the floor, depending on how we want the position of the wind to blow.
The second is on the ledge separating the living room and kitchen pointing toward the kitchen and hall leading to the rear bed room.
And the third is in the bedroom, on the dresser facing the bed.
This fan is really nice. It can be pointed in multiple angles, from parallel to the floor, to 90 degrees straight up.
The clip on fans just didn't seem to work all that well, and they had short life spans. These puppies work marvelous! We got them from Wall Mart.
Click here
WalMart has different flavors of the blower fan. If you want a good fan that actually "blows", get a "blower fan."..... you won't be disappointed.