This is the go to class on Oahu.
http://www.poakalani.net/ Look on left for calendar of classes.
It is the Saturday one. The class is at the beautiful Iolani Palace grounds in the Old Archives Building. You'll have to maybe circle it a little to find how to get in.
Cissy teaches it and her dad John Serrao the famous Hawaiian quilt pattern designer used to often be there. Look at the instructions as what to bring to class so you can start your project. This is a regular class and many of the islander and or Japanese snow birds take it so you can have a bit of a new comer feel but Cissy and John will make you feel at home. I was privileged over the years to have taken some classes and count it is one of my best experiences.
I always go to Fabricmart and have also gone to some of the quilt shops. At Fabricmart they will have the cottons in one section, poly cottons in another and yet another section for none cottons.
Remember the quilt shops will have many fabrics we have on the mainland too.
On the Big Island there is a quilt store in Volcano. If you happen to be there when it is open it is nice to stop by but in my opinion not worth planning around or making a separate trip. It is out of the way. Also it is cold in Volcano. Yes, there are places in Hawaii that are cold. I was ill prepared when I was there with a 3 month old and we both had inadequate clothing as we had just come from Oahu.
Many of the museums will have quilts on Oahu and in Hilo, Big Island.