The Ohlone Wilderness Trail is a 30 mile or so trail from Lake Del Valle to Mission Peak. I think it should also include the “approach” trail from Sycamore Grove in Livermore making it about 40-45 miles. If this extra section is included, it makes the trail very accessible by public transit on both ends. A two dollar annual permit is reuired to hike the trail (even if not camping). This can be purchased at Lake Del Valle Regional Park, or Sunol Regional Wilderness.
I like to tell people the the trail is really a mini version of the John Muir Trail. It starts at a large valley (Lake Del Valle instead of Yosemite Valley) and ends on a peak (Mission Peak instead of Mt. Whitney). Regardless of if you feel this is an appropriate comparison, the trail is very beautiful and well worth hiking. It goes through some very remote terrain, which feels especially remote for how close it is to the Bay Area.
It is embarrassing that I have yet to finish the trail given how close it is to my hometown, I still have about 10 miles left. My attempts to finish it have been thwarted for various reasons, including getting sick, fires, covid closures, and incompetent middle management. I will update the page with more info once I have finished the trail. As of December 2020, the trail is still closed.
For now here is a map and a picture of Murrieta Falls (a 100+ foot waterfall on the hike):