A reader left the following question in a comment:
We are looking for bike tours of the wine region in August. Can you suggest some?
That sounds like a great deal of fun. I'm hoping that by posting your question, readers other Washington wine bloggers might have suggestions to make in comments, or possibly repost the question for their own readers.
I don't know of any Washington wine bicycle tours this August; however, I do know that for several years there's been a bike tour of Yakima Washington wineries in September. There's an old 2006 Seattle Times article about them here, with some contact information. There's one this September of Wenatchee wineries; this is a striking culturally rich area of Washington. There's some information about it here.
What I'd be awfully tempted to do, is build my own wine tour by bicycle. You could look at the bicycle tour company itineraries for ideas. There are several. Then I'd match those against Washington wine tours, using these sites designed primarily for drivers, or those who are driven:
You could use books from the usual suspects who offer suggestions for bed and breakfast places, hotels, and restaurants along the way, though increasingly these too are listed online. I'd plan a day to rest at the end of the trip, and possibly the beginning too. Personally I'd pick a region—like Yakima, or Woodinville, and concentrate on it for your trip. The wineries are densely packed in these areas, but you could easily pace yourself, visiting two or three a day, at a leisurely pace, and still see some of the area. I note that, if you have any interest in beer, there are some very fine microbreweries in the area. I further note that if you decide on Woodinville, the San Juan Islands are not far, and are well worth a trip, and yes, there are wineries there too. The coast is incredibly lovely, and there are a lot of bike trails off the main routes.