In this particular situation, Costco is your travel agency. After the first delay, I would have called Costco immediately. As a travel agent, they could have potentially booked you on an alternative set of flights and saved your vacation. Minimally, they could have potentially arranged to have you hotel and flights extended by a day. That's the job of a travel agent.
The airline is responsible on for the flight portion of your vacation and is governed by their contract of carriage. You may want to search for it on HA's website. Again, the best option would have been to call Costco travel after the first or second delay and ask them how you were going to get to your destination. At the outstations, HA has very limited aircraft and very little way to substitute a new aircraft compared to other domestic carriers.