LA-San Diego would connect to the Antelope Valley Line at LA Union Station and add some more action with Metrolink, as well as BNSF, Amtrak, and Coaster. Possible locos should include the following: BNSF GP60 or Genset Switcher (for locals/switching), BNSF C44-9W or ET44C4 (for mainline freights), Surfliner and Coaster SC44 Chargers (with detail variations), and Amtrak P42DCs. An F59PHI (sold to Metra and no longer used on this route) could be added as a DLC, as well as an Amtrak P32-8BWH. The Metrolink EMD F125 from AVL would also be seen on parts of this route. The passenger cars would include the following: Metrolink Hyundai Rotem Cars and Bombardier Bi-Levels, Coaster Bombardier cars, Surfliner cars, and Amtrak Superliners. The commuter trains and Surfliner trains would have both coaches and cab cars.
I love that route! I did it on real world in 1994. But there is an important issue, in order to have it on TSW4: Route length! It is 180 km long. We do not have any route of that "size" DTG has increased lately the length of the routes, but they are around 100 km. So for it they will have to double it. Furthermore it is a route with several changes in scenery: city area in L.A and Sand Diego., then you have suburban areas, the highways, some areas with hills, and the beach too close to the rails. Hopes in the future we could have it.
Probably best to just do the section between LA and Oceanside. I doesn't have Coaster, but it does have the full Metrolink Orange County Line, though I think that only has 3 round trips, awhile it also has all 10 round trips with the Surfliner. Otherwise would have to do the San Diego - Oceanside section for Coaster service with 10 round trips and all the Surfliner services as if you wouldn't want to deal with merging the route with LA Union Station because of the Antelope Valley Line already running out of it. I actually don't know if this could be done either because of licensing from Coaster, but it could mean finally featuring San Diego in TSW, so how about that?