No, drones are not allowed in San Jose regional parks.
I am not sure whether you may fly a drone in the valley of Alum Rock, but rugged landscape will be a big problem for you to control it by RF...
EDIT/UPDATE: Short answer- no. Just called the Park Rangers and they confirmed no drones allowed. They said most National/State Parks don't allow drones anyway. Long answer: It's definitely outside the 5-mile-within-airport-radius (FAA restriction), so that won't be a problem. The problem though is if it falls under the National Parks ruling, any aerial craft is prohibited without special permissions. Also, what Ted said: hilly terrain interfering with your signals.
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