I would not plan to drive while on short call. Sure, not all the calls will be "get here in 2hrs", but I would say easily 75% of the time they are.
Remember the report time is the time you need to be at the plane, not the parking lot. The bus from the employee lot can be 10 minutes if you catch it perfectly or 1/2hr. Then if it is an Eagle flight you have to take the bus to the Eagles Nest. again, anywhere from 10 minutes to 1/2hr.
With 1 1/2 drive from SAN area (with no traffic) you would only make it if everything went right.
Trust me, every time you are running a little late, you hit traffic or the bus does not come or there is grid lot in the LAX loop and the bus takes forever to get to the terminal.
Still think you can do it, try a test run and see how long it takes you to get to the crew room at the Eagles Nest.
Also prepare your speech to the CP when he calls about your Missed flight assignment and you say , we I thought I could drive from SAN.