If you ever get down this way try Salmon Creek park in Clark County in the spring. It's loaded with huge concinnus'. 3 footers and bigger are everywhere in April or May. The Dupont/Ft. Lewis/Olympia area has some stunning blue pugets and even wandering garters.
Mercer slough is a good place too.
Eastern WA any wetland or water habitat will have plenty of fitchi.
Yeah it's kinda nice where I am because I don't have to travel far before the herps change. I can east, north, or south for less than an hour and find snakes that are different from what I find here.
Well I live right smack dab in a highly urban area. I don't exactly find snakes around my house either, although I did find a dead northwestern in the road a few blocks away about a week ago. But I don't have to go far. Perhaps 1/3 mile to the nearest "greenway" with a creek running through it. Plenty of concinnus' and northwesterns there.
Some of the best spots I know of in Oregon are just fragments of habitat surrounded by highly urban development. Heck, one really good spot has light rail service if that tells you anything. Highly urban.
I find more snakes some years in my yard than not. There's a few rat snakes livin under the house (awesome), a racer that shows up (really awesome), and the occasional rough green snake in the woods (back yard), but have found any in my yard this year