I'm contemplating circumnavigating Washington state, starting and ending at my front door in Bellingham. East across North Cascades Hwy to Newport, south through Spokane to Clarkston, west to Walla Walla and Wallula Gap then down the Columbia, north up Hwy 101 on the Olympic Peninsula and back to the mainland on the Port Townsend Ferry (if there is one next year). I mapped it out to about 1500 miles and figured it would take me a good three weeks minimum. The time commitment is the only thing that makes me hesitate to take it on. My busy work season coincides with the most pleasant cycling weather. I'm thinking of a combination of camping, friends, and occasional motels.
Even if I don't do the big tour, I'll ride all winter and throughout the coming year but probably won't do organized rides you have to pay to register for.