Ran from Stinson Beach early morning all the way to Mount Diablo late afternoon, passing by Mount Tam, San Rafael-Richmond Bridge, El Cerrito, Tilden, Briones, Walnut Creek, and Mount Diablo. Total mileage was ~65 miles and 10.8k of vertical gain according to my watch (Strava route mapping showed ~62 miles and 11k ft of gain).
I carried most of my food with me, but had some resupply stations set up along the way: I used a public spigot on the east side of Mount Tam coming down to refill water, then refilled water and food in El Cerrito at a pre-arranged station (no outside help), refilled water before entering Briones State Park (no external help, stashed water bottles that I threw in a garbage can when done), and resupplied water and got a couple of fruit juices at a Safeway in Walnut Creek.
Temperatures were warm but manageable until leaving El Cerrito, where it then became very hot going more inland toward Walnut Creek and Mount Diablo. Estimates were 95-105 degrees in those areas.