I might suggest installing vent covers (MaxxAir, Camco, or similar) over the roof vents. That way, you can leave the vents open more than just a crack, to provide better ventilation and less humidity build-up, without having to worry about rain getting in. You might also want to get the insect screens for the refer, WH, and furnace vents - mainly to keep wasps from building nests inside them. Finally, fill in any gaps on the outside of your rig with steel wool or "Great Stuff" to keep out any critters that might want to make themselves at home while you're not.
2013 Eagle 266RKS
2011 Ford F-150 w/3.5L Ecoboost & H.D. Tow Package