I'm going to vote for the one-way car rental here. It can be inexpensive if you search around and will allow you to return directly to the airport. You won't save much (if any) time using the Eagle flights, to be honest, by the time you factor in parking, going through security and taking the bus to the remote terminal. Then, when you get to SAN, you have to do the inter-terminal transfer and go through security all over again. Driving the route is a wash, time-wise, but it gives you a sense of time control.

The other thing I'll say here is the CRJs are miserable creatures. Don't mind CR7 and CR9 equipment (only occasionally seen on the LAX-SAN route), but the CRJ is terrible.

Much rather be driving at that point.

The final thing I'll say is that LAX is currently doing runway construction. The last two times I've flown out we've had to taxi over to the north side for departure due to construction. From the Eagle remote terminal, that's quite a long drive, almost the distance from LAX-SAN (not literally but sort of).

I really wish they had a remote check-in operation at the Eagle terminal so those pax originating or ending at LAX on Eagle could go directly to the building.

Nevertheless, one-way rental is not a bad way to start this trip.