If you get over to the area of Del Amo/Wilmington/Alameda it's a truck friendly area and can probably find street parking, but I cannot guarantee it. There's RR tracks along Alameda, but I haven't been over there in awhile. I'm talking the area between 91 Fwy on the North, 405 fwy on the south, 110 fwy on the west and 710 fwy on the east. Lots of industrial, maybe pull in to multi usage complex and park in the back ? There are state scales on the 405 near Figueroa which I believe are closed permanently, but are accessible to park. But again, can't guarantee it.
since you posted in swift thread, i assume you drive for swift. we have a intermodul yard in montebello. slauson and chapin of i-5. yard is on chapin rd. from the 5-go east on slauson, go about 1/4 mile to chapin and make left. yard is on the left about .5 mile