My friend and i checked out the Morgan Territory which is adjacent to Mt Diablo in the East Bay. Very nice views of Mt Diablo but less than rewarding because it is heavily grazed and wet and mucky. The cattle eat all the vegetation and very few wildflower blooms, but still worth checking out. Although this it has some beautiful woodlands and grasslands, there are much more scenic places in the area to hike including Mt Diablo State Park next door.
