Hi Paul-
Moscow is a pretty little college town and KPUW is a nice little airport in good condition, perhaps primarily b/c Horizon Air (Alaska Air's commuter subsidiary) flies 1-2 flights a day out of there. I flew out of KSFF in Spokane and routinely flew down to KPUW to do research at WSU. Nothing particular out of the ordinary around PUW. It's far enough away from, and on the windward side of, the Rockies, so not many issues related to terrain turbulence. Your consistently good weather flying happens generally from May to mid-October. Between November and April the weather is much more variable. Some days good, others not so good. Compared to where I live now in the rain shadow of the Cascades in Central Washington, there are far fewer days in E. Washington that are good VFR days because the clouds start backing up against the windward side of the Rockies, but you should still find quite a few. January and February in particular you'll find quite a bit of low clouds and fog. I'm not aware of any RVs at Pullman, but there are a pretty good number at Felts in Spokane and in Coeur d'Alene at KCOE.
Hope this helps a bit. Good luck.