There are all kinds of track plans out there, just not necessarily what you are looking for.
You have about three choices:
1} google earth it to get an overview and selectively compress to the areas you really want to model to be "prototypically" accurate and create your own layout plan from the real thing
2} adapt someone elses track plan for your use to represent what you want to portray- "proto-lancing" your area or desired modelling.
3} Create a whole track plan of your own liking that includeds only what you want to portray based solely on your desires and not necessarily the real thing..."freelancing".
There most likely will not be a "ready-made track plan" for you to copy that has the areas you want to model.
As mentioned there may be knowlegeable models representing the area you are trying to model, but even he may not have a ready made plan for you to copy.
You would need a warehouse to model the LA area In Z scale {really tiny scale} to represent the total area...WITH selective compression still built in.
Even the "All ready made plans" that ARE based on reality have "selective compression" built in. That is the long boring mileage between scenes is taken out or shortened; the areas more accurately portrayed are shortened or condensed; or the important operations parts the modeler wants to work with are only represented {such as the local yard for for yard consisting or an engine servicing facility, or the local RR-utilizing business is built}
Good luck in your planning or of finding a trackplan that works for you!

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