The weather was perfect for us. The day before had been overcast and even had a hint of rain, so we lucked out with the drive weather.
Also, the route planning was partly done just with Google maps aerial photos, and the surprising group of picturesque available parking spots in the map turned out to be true when we got there.
(I had been secretly crossing my fingers the whole drive hoping that the spaces would be clear.)
In the busy SF bay area it is a bit rare to find a good set of empty spaces in a nice location like that.
One thing I am learning from these drives is that there isn't really a "one size fits all" pace. We had a group of 5 roadsters in front wanting to push the limits of their cars, and a slower group in the rear that felt a bit left behind at times. In hindsight I wish we had spent more time at the beginning discussing upcoming "split up" and "wait for stragglers" strategies. Also, with that many cars, there isn't always a good stopping place to get everyone back together again. A more thorough route plan could include some part way points where we would stop and regroup before continuing on. Still, in the end, it all worked out well in terms of getting the cars together at the photo spot, and making it over to the great lunch place after the drive.
In case anyone is wondering, no, I still don't own a Roadster... It was courtesy of Spiderguy's fantastic generosity that I manged to be part of another one of these fun events.