Hey @Kevin - Bay Area,
As @Robert M mentioned, Tour d'Hoe has been a more intimate affair. I started this event several years ago as a 1 day tour (the weeken after Labor Day), starting at the Holiday Inn in Auburn and winding through the foothills and Tahoe National Forest before arriving for lunch at Meeks Bay or Sunnyside, then head home by way of 89 through Emerald Bay and back down 50 to 49.
In 2015 it grew to a two night stay in South Lake Tahoe with some participants arriving Thursday in Auburn with a barbecue at our house that evening. It was a well attended affair with approximately 15 cars and 35-40 people. Noel arranged the hotel, Mitch and I worked out the drive.
The following year saw a smaller turnout for a 1 day drive.
We tried a two day event again in 2017. The initial response was promising, the net result wasn't. We didn't meet the minimum at the hotel so I had to take an extra room. I didn't make the event due to a family emergency that took us to Salt Lake that weekend. The trip up found our hapless participants stuck in a monumental hailstorm.
Last year reverted back to an optional overnight stay in Tahoe. It was organized by @Ryan (formerly) in NorCal and was attended by a small (7-10 cars) but enthusiastic group.
I think an event in the Napa/Sonoma region will draw a good sized crowd. Practically everyone I talked with at this years West Coast Cruise expressed great interest and desire to attend. Having it later in the year would be a big plus. Andie and I would be there for sure.