I like to compare the cheapest currently available fare vs. a W fare.

The lowest fare I see available for sample travel in September is $660 a/i r/t (two T fares, both directions about $300).

The W fare I see for sample travel in September is $847 a/i r/t (two W fares, both directions about $400).

To find the fare difference I used matrix.itasoftware.com's route language -- I wrote that I wanted advanced routing codes "f / f bc=w" to only look at nonstop travel booked into W. I also could have used continental.com's advanced search and specified that I wanted to buy fare class "W".

Why do you want a W fare? In the new MileagePlus program (which we're not sure when it will go live) you can use a CR1 or a SWU on any flight from mainland U.S. to Hawaii with no fare restrictions.