Stephen,
For hiking in the rain your legs would get wet from side spray or pack drippage long before condensation would become an issue. In light rain, with the baselayer protecting the skin, you get a heat pump effect. I am mainly at altitude (afternoon thundershowers) or on the coast ( morning dew on overgrown trails), but for PNW like conditions I would add yet another layer, the rain kilt. WPB rain pants only work well in cold weather. Umbrellas are great for downpours and shade, but don't work for my hiking conditions.
I tried the Tilley Hat/ Seattle Sombrero route, but again, not for me. Pit-zips are great for breaks in the storm and uphills. I'll be DIY'ing some on my Mica soon. Enjoy.
stephan