On the other hand, I'd like to give robot_grrl the option of having that day. So, I have done some poking at schedules (at least as they sit today), and inquired with Google, and have come up with an idea of how we can do this -- provided that Tara is willing to do the drive to Pasadena herself. (Derrick will probably be in Illinois with his grandparents and won't make the con).
The route recommended by Google, which had become one of two I'd been considering, has me taking The Coaster from work only as far as Solana Beach -- the alternative would have been to take The Coaster all the way to Oceanside. From there, I'd board Amtrak's Pacific Surfliner and take it to Los Angles Union Station. Finally I'd catch an LA Metro Gold Line train to the Del Mar station in Pasadena and walk to the hotel (about half a mile).
The only gotcha, other than the possibility of the train schedules changing, is what combination of trains to catch. If I catch the Coaster #653 which leaves Sorrento Valley (by work) at 4:05, and arrives in Solana Beach at 4:14, I should be able to catch the Surfliner #785 at 4:35 and make it to LA Union about 6:45pm which would get me to the hotel by 8:30 or so (guessing here). But, Google reports that "Amtrak recommends arriving to the station at least 30 minutes before scheduled departure." This would say that I'd be cutting my time in Solana Beach shorter than recommended.
On the other hand, I could take any of three Coasters (including what I normally take home now, the aforementioned one before it, and the one after), and safely make Surfliner #589 at 6:29 (possibly with a long wait at the Solana Beach station). But this wouldn't get me to the hotel until 9:45 or so.
Honestly, I suspect that as long as I made the earlier Coaster, I'd have no problems making the earlier Surfliner. I wouldn't be taking any luggage -- what I'd need would be in Tara's car. So I'd just have to get from one platform to the other (using the sky-bridge 50 or so feet above the tracks) in twenty or so minutes. As long as I picked up my tickets before-hand (or had them mailed to me), I'd probably be in good shape.
Doing one more look, it doesn't appear that there is an alternative using The Metrolink (at least not based on current timetables). The only afternoon departure that connects Oceanside to LA Union leaves Oceanside at 3:35, which would not be easily reachable from any Coaster I could sanely catch.
But, when all is said and done, Tara may end up working, or may choose to wait for me to get home. If we move from Oceanside before then, this may also impact how we, or I, get there at least slightly. Although, the worst case I could see is that I'd have to buy a one-way ticket on The Coaster since I'd no longer have a monthly pass that covered the trip, and would either have to leave my car at work through sometime on Monday, or would have to have Tara take me to work in the morning.