I am having a problem keeping road spray from coming in to my living quarters through the refridgerator vent and pooling on the floor in my living quarters.  This is only a problem when I am hauling.

I live in the Pacific NW where the roads are wet a lot and there can be a lot of road spray.  I talked to the manufacturer and they claim they've never heard of this problem which I just cannot believe! 

Does anyone here have any tips or tricks on what to do with the vents while the trailer is on the road?

Never had that problem, and we have quite a bit of rain as well. Most vent covers are a  stamped single sheet affair, with no inner panel to deflect water.

One thing you could try, is installing part of an automotive window vent visor cut to length on the front, vertical edge of the vent. This would effect a low pressure area over the vent cover, and pull the air out of the vent.  It is held into place with tape and would not need tools for attachment. Hopefully this would end the water problems.

http://www.car-stuff.com/windowventvisor.htm