Rent a car and drive there.
I am a visitor and don't plan to drive. Any other recommendations? Is there a coach that I can take? I note there is this Outlet Hop...
Look into Outlet Hop, because it's a really difficult proposition to get from San Francisco to Vacaville on regular public transit. It looks like it would take a train and 3 buses--BART and then 3 buses, taking 2.5-3.5 hours.
What exactly do you want to visit out there? Maybe there's someplace closer to San Francisco that can meet your needs.