I'm sure there are a good number of yurts in Washington. There's also quite a difference, and distance, between Eastern & Western Washington.
is in E. Washington.
is near Seattle and likely has a demo yurt or two up. I recall a camping-style yurt maker somewhere along the Columbia too.
In my neck of the woods (Washington/Idaho border), I know of half a dozen or so yurts (including mine). There's even a bed & breakfast place a few miles down the road with a yurt.
Contacting any of the major manufacturers would be a good way to find out if they have any purchasers nearby willing to give you a tour.