Air movement is the best defence for condensation .
Even if it is cold outside you must evacuate the moist air trapped inside.
Cooking , the propane flame , breathing, wet clothing....all introduce moisture to the interior of the unit.
IMO keep the forward and aft vents open a crack to bring in fresh air and exhaust the stale air. It doesn't hurt to run a (exhaust) fan to exchange the air more rapidly and if it is cold weather just a short time will help .
You will find it more comfortable as soon as you find what works for you to get that "wet air" moving and out of your rig.
Believe me I am familiar with condensation... I lived on boats for many years.
If you are finding moisture in cabinets and you are positive there are no leaks try leaving the cabinet doors ajar to dry them out.
It is the warm 'moist' air hitting the cold walls of the cabinets turning to condensation.
Again... get that air moving and exchanged.
Always Use the exhaust fan on the stove when cooking but open a window or a vent to allow fresh air to be drawn in at the same time.... if you don't it is just creating a vacuum.
hope this helps
'07 WildCat 30 RLBS ~ West Coast Edition ~
Trail Air - Tri Glide Pin Box
2000 F350 DRW 7.3 Diesel Lariat 89k miles
Edge programmer, 4" SS exhaust turbo/back
Vancouver Island, B.C., Canada