Technically, there are a lot of large counties which have networks of "local" transportation where you can get from one end of the county to another without lea

Technically, there are a lot of large counties which have networks of "local" transportation where you can get from one end of the county to another without leaving a single system. For example, in San Diego you could easily get from Chula Vista to Encinitas on MTS buses. It may take you a lot of transfers. But this example is, arguably "outside of cities" because San Diego County is a large, densely-populated area that's made up of many more cities than San Diego proper. The same goes for Los Angeles and counties of the Bay Area. I think the challenge for a "local-only" expedition is where one county ends and the other begins, and the local bus service may not necessarily serve a convenient point to transfer in-between.