Pub crawl is definitely worth it, especially since you haven't been to Negril or the west end before.. I suggest you do it early in your trip that way can go explore the cliff area on your own later on.
And you did good picking CSA for your first trip to Negril! Its a great resort on one of the nicest stretch of beach ,and the location gives you easy access to the rest of Negril. Be sure to do an early morning beach walk(to the left if facing the water). Also grab a drink(or bottle of sparkling wine) and stay on the beach for sunset. Its one of my favorite times of day there. Truly magical. Hope you enjoy CSA and Negril as much as I do. Im sure you will!