Passenger ride from West Hawaii (Big Island) to California Coast

[Wes]

I moved to Kailua-Kona over 2 years ago, and I am ready to go back to Colorado.... To make it more fun, I am wondering if there are passenger freight ships that take that path... and if they have to do that "foreign country stop" law like cruiselines going U.S. to U.S. They just have to have a U.S. flag, right?
And, how do I get started researching it?

[lunamara]

Jones Act will keep you from going on a foreign flagged vessel from one US port to disembarking in another US port without visiting a foreign country.

 Try checking the routes of those few cruises that go round trip from US (San Diego/LA) to the Islands. Next question would be if the cruise line will let you do a partial trip. A good travel agent familiar with the cruise lines can help.

No freighters taking passengers have this route.