Vallejo is north of the San Francisco Bay area, not a lot of tourist draw up that way. Although they do actually have a smallish six flags Amusement Park in Vallejo which I've only seen any of the roller coasters moving maybe 2% of the time I drive past it. Really, if you are visiting the region, you'd only want to drive through Vallejo on your way to Sonoma or Napa if you like wine country... :)