Are you asking this as an Australian yourself? This is kind of a strange selection of cities to group together (even assuming you meant Santa Clarita). Lancaster and Santa Clarita are LA County, and Riverside is a part of the Inland Empire. The cultures throughout Southern California are definitely similar but being that the region is so sprawling, there will be different norms in different areas.

Speaking for Riverside, yes, you would be out of place as an Australian. Speaking rather bluntly, there aren't many "foreign white" people there so people would likely bring up your accent incessantly.

I have no idea what the "punch above their weight" bit means but hopefully this answers your question.