If WN has a zed agreement with Hawaiian Airlines, they have a non-stop from JFK. Other options to avoid the west coast would be ATL (DL), ORD (UA), DFW (AA 2x/day), IAH (UA). MSP, SLC, DEN & PHX are also options but not sure if that is too far west for you. LAX has the most options with all the Hawaii-bound airlines offering several flights a day. You may want to consider a west coast connection as a back-up especially for the return trip. Hawaii is a popular destination, with many non-revs saving their highest priority non-rev pass (D1 in the case of AA) for a trip to the 50th state.

Not sure if we have any HA employees here but there are a few UA folks here who might have better insight on the IAD & EWR flights as far as loads or weight restrictions go.