FYI: Several RUSA permanent routes go through Mt. Diablo, but they will only be do-able on the weekends since the park is installing new bike turnouts during the weekdays. The work will be ongoing for several weeks. In the news:
https://youtu.be/C1PABpFA4GA?si=LvV0SYDqf7THCnPc
I rode the D today, but have to recommend that anybody riding it on weekends to get a very early start...the traffic starts to get annoying and even dangerous around 11 am, even with the existing turn outs.
--Kitty