You may wonder how Printing can be an activity. You're right, it's not but this is something you could think about and take advantage of your stay in Koh Chang to bring back with you your own printed articles.
Products in Thailand are quite cheap compared to European countries for example and it could be a good opportunity for you to get your own business cards, own t-shirts or caps with your logo, own mugs with your pictures, or any other printable objects.
I recommend you!
I recommend Pasteldesign as the best place you can find in Trat province. They can print all that you want on almost all kinds of material. They are based in Trat but they can arrange the delivery to Koh Chang.
The best way is to contact them in advance to be sure they can do what you want but will also be available during your stay. Then you can plan with them a visit to their working place if needed or delivery once you will be on Koh Chang. Just contact them to get more information.