Are you doing a ballpark tour?
Yep. I'm going on Sports Travel & Tours. The tour itself goes to Phoenix (AZ Diamondbacks), Anaheim (Angels), L.A. (Dodgers), Oakland (Athletics) and SF (Giants).
I'm tacking on a few ballparks on my own as well: Seattle Mariners, San Diego Padres, Pittsburgh Pirates.
The reason I'm using the tour for most of those CA ballparks is that some of them, such as Dodger Stadium, have no mass transit access, so I would have to drive in order to get there - and I refuse to waste my vacation time driving.
Plus, I know for a fact I'd get lost if I tried to drive in California.