First, get yourself and your bicycle to the Antioch BART station. Detrain and then immediately take care to navigate a highway interchange. Soon afterward, you’ll ride on a multi-use path that will take you to the first dirt section of the Black Diamond Mines Regional Preserve.
The first Stewartsville trail becomes steep quickly, but once at the top, the rollers are moderate. The views of neighboring Diablo Mountain are ominous, but not to worry, you won’t climb anything as bad as the beginning! At the top of the third major crest, there are some fabulous views of the valley where you are headed. Then, you descend spectacularly and into the City of Clayton.
When at the urban bottom, you’ll climb more on dirt trails steadily until a crossroads, where there are several different ranch roads. You’ll pick the one that’s legal and then descend again downward to get to a bridge that then takes you up another set of foothills.
The last set of dirt rises and falls over small hills. There is even a little singletrack mixed in, which is a pleasant surprise. These trails are in the foothills of Walnut Creek, so they may be a little more popular for hikers.
Last, you’ll descend in Walnut Creek for a bite to eat and beverage. Afterward, take your train back to where you came from!