So the experience with Matson went very smoothly! They have a ship, the Mokihana, that leaves from Long Beach, CA every Saturday. To make that trip, the car has to be at the port by the Wednesday before. Weather and conditions permitting, It takes about 4-5 days to sail from Long Beach, CA to Honolulu. Once in Honolulu, I was told the Waialeale sails to Hilo on Mondays, and that my car may or may not make the Monday sail. It would depend on how much cargo had to be unloaded and loaded at the dock. My car apparently made it and was in Hilo and ready for pickup 2 days later on that Wednesday. If it had not been loaded, it would have sat at the pier in Honolulu and loaded up on the following Monday.
Car was a little dirty, but nothing too bad or unexpected. Overall, it was in great shape to be honest. They didn't even charge me any storage fees.
One small tip - email support did not have the most updated information, but whenever I called, the folks were very nice and very informative.
I had a very good experience overall, although I know a lot of this process can depend on the weather. When I do ship a Tesla over, Matson has earned another shot with me.