Not sure about a bus that goes directly to the Winchester house but a cab/uber/lyft could get you there no problem. It's possible a city bus could get you at least within walking distance. However, San Jose is at least an hour away from San Francisco. Depending on the day and time it could be longer drive time therefore higher rates might apply. It may even be cheaper to rent a car for the day, stop in San Jose on your way and then continue to SF after your visit. Winchester house has a private lot with ample free parking. Tours are every hour, if you get there early they have a great gift shop, café and portions of the property you can tour on your own while you wait.
The house is located in San Jose, I would drive to the house on your way to San Francisco would be the cheapest route.
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