Two comments on the viability and marketing sense of an air-rail program for trips originating in Hawaii. The first is the obvious problem that it would be primarily air and proportionately not much rail. The second is that, in today’s air fare environment, you are probably just as well off booking the two modes separately particularly since you could likely beat any package price Amtrak could arrange for the small Hawaii travel market.
Hawaii is the most isolated population center in the world. You folks are nowhere near anything out way out there in the Pacific. The flight from Honolulu to LA is 2550 miles each way: a longer flight than New York to LA. So, just to get to the nearest possible gateway for Amtrak travel, you would fly the equal of a mainland transcontinental trip. If your desired rail segment was LA to Chicago, for example, you would have a flight distance of over 7000 miles and a train ride of maybe 3500 depending on how you went. To make this work, Amtrak would have to compensate the airline for your two lengthy plane rides and still have something left for the rail portion. Airlines would be reluctant to commit to low fares for an entire year for the very small number of passengers an Amtrak package would generate from Hawaii. My guess is that we would be talking about $800 for air and two-zone rail for Hawaii origination.
Air-rail trips originating in the 48 states are usually one way rail and one way air. What makes air-rail sometimes attractive for those trips is the relative high cost of one-way air travel (that is less true today than a couple of years ago). But, even for origination in the 48 states, it is often possible to independently book the air and rail separately and beat the package price. Out of the competitive Philadelphia air market today, I am certain I could beat the air-rail package every time. Travel originating in Hawaii using two lengthy air segments would be even easier for independent booking to beat air-rail.
Flying from Hawaii you would fly to a mainland city (say LA), ride the train, and then fly back probably from a different mainland city (say Chicago). Booking this yourself you have a choice of air carriers. As an example, the fare for travel in October HNL-LAX and return ORD-HNL would be about $450 on Northwest or ATA. Add in about $250 for Amtrak coach travel LAX-CHI, and you come in at $700. Amtrak would have a very tough time beating that cost for an air-rail package.
Living in Hawaii has lots of great attributes, but convenience to travel in the other 49 states is not one. I think Amtrak sees only a minimal market for air-rail packages out of Hawaii and, with some astute travel web site surfing, you could almost certainly beat what Amtrak could contractually arrange.