i suggest not planning anything else until you are there --- you may or may not want to do anything else -- especially your first time in Negril --- just walking the beach and stopping for food and drinks is an adventure especially for a first timer
you may want to plan a half day on the cliffs - checking out some of the hotels up there and feeling the cliff vibe
i hate to set an alarm clock on vacation and usually will just get up - find a driver - very easy to do - and go where ever i want
warning: that sand gravity can grab you --- some trips i spend my entire time in the lounger --- bug eyed lol