Yes, we are North-East, not far from Canadian border. A lot of snow, cold winters. We haven't lived in SE WA but visited the area you mentioned 3-4 times. The area between Pullman and, say, Kennewick. Way fewer trees, lower altitude but winters are less cold and less snowy. I would say there is no perfect place. Once you checked your main checkboxes, paradise is a state of mind, not place itself. You will have hot summers. We are at higher altitude, I have tractor primarily for snow but summers are much cooler. And we like cooler summers. This June was mostly at 68-75F, our german shepherd and I love it. I talked to a person from Texas and he mentioned 90-95F in May and 95-100F in June - no, thank you very much. We even bought land in HI at 3000 ft elevation to have 75F in summer and 72F in winter for the same reason.

South-East WA will have hotter summers, no shade from trees and every time we visited it was windy. having said that rolling hills are beautiful, farmers are nice, some healthy rivers for fishing. Pullman and Moscow have shopping and amenities.