AN: you have to start somewhere, but money is finite. I’d argue that:
(1) If possible, extension of the light rail to Sorrento Valley (and interconnection with the main coast line trains there)
(2) Double tracking as much of the main coast line as possible between L.A. and San Diego.
(3) Electrifying the same (watch the NIMBYs scream “OMG … EMF!”)
(4) New Coaster station at Del Mar Heights Road
(5) Separated bikeway and/or walkways roughly parallel to Del Mar Heights road. Bus transit from One Paseo to the Coaster.
… would be a better use of money than a light-rail extension that dead-ends at One Paseo. Unless the developers want to pay for it themselves.