#1 for MAILING ADDRESS one can put private in front among other things. Instead of PO Box one can put "private box ####". Family trust does not have any SSN or an EIN.
#2 put stickers on the bumper that read "PRIVATE" or "NOT FOR HIRE" ..put it on the tag even or on the USDOT decal..depending on how you do it
#3 One can send memorandum of law or the like indicating your reservation of rights or the like, your intent so as the clarify. Keep the 'application' form and related documents on hand. Or at least copies thereof.
There is a drop-down on the online USDOT application for UNKNOWN STATE..not sure of the usefulness of that selection.
#4 Interstate selection only removes it from being intrastate. No 'State employee' relationship ..its interstate.
#5 "near" before CITY, STATE is to remove 'resident of city' presumption.
Should read private box not PO Box. There is such a thing as a "private box" or a "private bag". Private != resident (public office holder). Not domestic = not U.S./Metro Federal/state employees are neither private nor non-domestic. 'near' City, State is to remove the presumption under a city-residence contract.A division of a private family trust that I oversee has a USDOT # with a not domestic PO Box and a fax # --no other contact info.
Example:
private 40 Baker Lane
near Chicago, Illinois not domestic
private box 9493
near Chicago, Illinois [12345-9493]
One can ask about the +4 numbering for the private box.
General post office is also an option.