If your RV is small, you can camp at Mount Diablo State Park during your visit to the Fremont area. This park has three separate campgrounds; they are called Juniper, Live Oak, and Junction. Juniper is the largest, and it has the highest elevation of the three and offers easy access to the hiking trails.
From the summit, you can sometimes see the Farallon Islands and Mount Saint Helena. This peak is the main attraction of Mount Diablo State Park, but the hiking trails and rock formations are popular too. If you like to stay at primitive campsites, then you’ll love this park.
“…Most of the sites are shade-covered, which campers will appreciate during the hot summer months. Some of the sites have outstanding views of the bay, while others are tucked away and more secluded…” – Linda, sfbaynatureplay.com