This year, they approach Sonoma via Trinity Grade, a nasty little climb that I've been up once, having descended the side they will be climbing several times in the Santa Rosa Cycling Club's Terrible Two Double Century.
When I climbed Trinity's backside, I came up from Napa on Mt Veeder Road, a gorgeous stair steppy type climb. The pros will be going up Oakville Grade, which I have never gone up, but have ridden down. Eagle Cycling calls it Without a doubt the toughest climb in Napa - ouch!
1) OAKVILLE GRADE (from Hwy 29) 650 ft/mi. Without a doubt the toughest climb in Napa. it's not that far but it starts out tough and gets alot tougher. You climb 650 feet in exactly one mile. No breaks, no shade, no fun. The first half isn't so bad and I can manage it sitting in the saddle using my 39/28. The last half increases in pitch and it's standing and grunting all the way at a 3.5 mph pace.
Trinity would be a great place to watch the race explode! Come to Sonoma and check it out. Make a weekend of it - there is still availability at Le Tournesol in the heart of the action!