I lived in San Diego and did a lot of track events. I'll break the tracks down by distance for you:
2 hours: Auto Club Speedway (formerly California Speedway) is the closest, but it's very high speed and not very technical, and it's also a lot higher priced than other tracks, so I wouldn't recommend it.
3 hours: Willow Springs is the next closest, and they have 3 tracks there so it's a good "home track" for you coming from SD. I love all three tracks there, you will have the most opportunities to run Streets.
4 hours: Next closest is the Buttonwillow. This is also an amazing track.
5+ hours: From there you are looking at going out to Vegas, where they have Vegas Motor Speedway (similar to Auto Club Speedway in setup) and Spring Mountain in Pahrump (another phenomenal track).
Also 5+ hours away is Phoenix, where they have AZ Motorsports Park, Phoenix International Raceway or Firebird Raceway.
After that you're looking at going up near San Francisco to Laguna Seca, Infineon, Thunderhill and Reno Fernley.
That pretty much sums them all up. If you want to know more about any of the tracks, I've driven quite a few of them so I'm more than happy to share my thoughts on them. For more track info, check out Trackpedia: http://www.trackpedia.com/wiki/Main_Page