mt diablo is great for exercise- can do hours of climbing, but mostly just fire roads. there are a handful of legal single track – Dan cook trail at the entrance of south gate being one of the more fun/accessible ones. some fun less legal single track. but, by and large, do diablo for exercise/nice views. diablo mud can be unridable in some areas after a rain. can get super hot in the summer
close by, Joaquin Miller has some more advanced trails, nice and shady in the summer heat and handles the rain better. poaching here is not as necessary and can be met with aggression- generally don’t. small park overall
Tamarancho in marin is great. totally worth the 45 min drive.
rockville is about 30 min away- fairfield. great park- can find anything from easy fire roads to full double black. climbs never too sustained. not a huge park- just go explore, can’t get that lost.
skeggs- cool place to go. redwoods. different cool loops. worth the hour ish drive.
summertime- tahoe, downieville!!!!