Hello to the group.
I heard there was previously a nude B&B in Leavenworth but that closed down a few years back.
If your travel options include outside of WA, there is a nudist B&B in Bend, OR.
There is also a nudist B&B in Pasadena, CA. i have actually stayed at that one. It's a nice place and the owners are really nice folks. I was kind of bummed that they didn't have a pool with it being in So. Cal.
I stayed at one in Leavenworth while on a contract, just one night. Pleasant people, nice room detached from the main house. It was winter so I only used the hot tub and visited with the owners in their adjacent house; the husband went nude but his wife did not (I don't recall how dressed or undressed she was, but she wasn't nude).
It was about 6 or 7 years ago as I recall. They had a public name for the place, and one for naturists, so when someone called, they knew immediately if they had heard about them through naturist circles.
So if you searched for it in textile sources you wouldn't find it as a naturist place.
It might be worth it to try the number listed on their web page and see what you find out.
https://nudehiker.wordpress.com/2008/10/05/havanese-heaven-clothing-optional-in-leavenworth-wa/
Is that one on Whidbey still open?
I have stayed at one in Surrey, BC. Bare Creek is its name - honestly - they bought the place, which is very nice, and afterward found out the creek nearby is named Bear Creek, so when they started the B & B the name was a natural (pun intended). That was just 2 years ago this month that I stayed there. You just rent a room in their large well-appointed house. They have a good hot tub. At time I think they were running one of the nudist swims in the area, and they have nudist get-togethers at their house. I was in town for a conference so didn't get back to the house in time for the gathering, regrettably.