IMHO, zoning is is one of the biggest challenges facing anybody who wants to do something interesting in real estate. CA actually is forcing cities to make it easier to build ADUs: http://www.hcd.ca.gov/policy-research/docs/17Jan30-ADU-TA-Me... . Worst case, we put wheels on them and have license plates to avoid having to comply with building regulations;)
I hate to be that guy but "putting wheels on them" is not a simple solution at all... it will take a lot more than that to make your cargo containers street-legal.
> Worst case, we put wheels on them and have license plates to avoid having to comply with building regulations;)
Once they are vehicles, it's much easier for them to be impounded for violating parking and other vehicle-related regulations, which the proposed uses seem as likely to break as building regulations.