This park is one of eight National Parks in California and should be on your list. We spent just one weekend here with camping. The rock formation is interesting here. For hike you should choose cold seasons. We hiked in October and was really hot. Hikes do not have lot of shade.
High Peaks Loop
We did just one beautiful hike and we were happy. Trail is 6.3 mile with elevation gain about 1700 feet.
North Wilderness, Bear Gulch and High Peaks Trail loop
We did also very long trail in Pinnacles. It was 14.2 miles. Part of High Peaks are difficult but overall is moderate trail with flat section.