Not far from where I live in Morgan Hill, is a the largest state park in Northern California and the second largest in the state. Situated in the Diablo Range and spread across Santa Clara and Stainslaus counties and containing over 87,000 acres the park has several hiking trails with several levels of difficulty.
The park holds many scenic views. Some of these include peaks like Pine ridge, middle ridge and blue ridge. Mount Sizer is the tallest point in the park.
I hiked a few miles of this park on a hot September weekend. It was tedious in parts, but manageable. It was well worth the trip.
Bay Area Bloke 