Dehumidifier?

Two people and two dogs definitely generate a good deal of humidity.  But, I'd likely not worry about bringing along (and trying to find somewhere to setup) a dehumidifier while camping.  As teckntrek suggested, cracking a window or two along with the roof vent is likely the best way to go.

I, too, live up here in the PNW in the coastal community of Open Sores (Ocean Shores). This is a darn dank area. I've used a Dry Wave R/V air dryer in each of my trailers over the years. It's done a good job of controlling the moisture and musty smell when the trailers were not in use. I think the Dry Wave is available on Amazon.

Also about your other post. I always left my previous RP 175 and our Kodiak replacement plugged into an extension cord from the house whenever at home. Both trailers have the same model converter and each a garden variety Interstate group 24 RV battery. In the last 6 years I've never had to replace a battery, and I've only had to add water twice. We have used both trailers a ton, including a considerable amount of dry camping.

The dealership where I got my used 177 recommended I get a dehumidifier. Do any of you have size recommendations? Most of the time I'll be on hookups so I will be able to power it.  My Rpod will have myself and 2 dogs, the largest is 40lbs. I'm also in the PNW where water on shoes, paws and fur won't be uncommon.