For an additional $2.50 (buy a $3.00 day pass on LA MTA instead of the $0.50 one-ride from Long Beach), you could ride transit all the way to Thousand Oaks in Ventura County on the LA Metro Buses. For another $4.00 on top of that, you could ride to Santa Barbara on the VISTA (actually to Goleta, a little North of Santa Barbara). That would make it a total of $11.65 to go from San Diego to Goleta. Not too bad.

I'm too lazy to map out the most advantageous routes (especially within LA), but it would probably involve some combination of buses from LAX to Hollywood to Universal City to N Hollywood, connecting there to the new Orange line (express bus from N Hollywood to Woodland Hills, connecting to MTA line 161 to Thousand Oaks, connecting to the VISTA Highway 101/Conjeo Connection to Ventura ($2 fare), connecting there to the VISTA Coastal Express (another $2 fare) to Santa Barbara and Goleta.

That would be about 220 miles for $11.65 and would easily take all day. But it would be a very inexpensive way to get from UCSD to UCSB. Get an early start.

It may very well be possible to continue Northward from SB or Goleta on public buses - again, too lazy. I'll let someone else continue the route.