The 105 distance is apparently almost full... (It's limited to 500 riders.)
It sounds like there will be a prime on one of the hills, using chip timing.
More from the website FAQ:
Q. Who is this ride for?
A. It is for EVERYBODY.
For professional cyclists, this is an opportunity to stretch your legs in an event that fosters competition in a relaxed environment. Timed course? Check. Mid-course premiums? Check. Peloton dynamics? Check. The pressure of a hundred television cameras, roaring crowds, and a director sportif yelling in your ear? No, not really.
Let this represent a return to your love of cycling: epic landscapes, grueling terrain, and rich camaraderie with your peers. Take some time out from your race schedule to experience the best professional cycling has to offer to the best professional cyclists.
For recreational cyclists, this is your chance to ride with some giants along a route long celebrated for its intensity and beauty. While the way is long and steep, there is fixed and roving support, including repairs, food, and water. If you've long wanted to roll along the elegant coastal hills of Sonoma County, you won't get a better chance than this. This is an athletic and personal achievement you'll be proud to tell your kids or your dog about.