We suggest getting off the resort at least once. Taxis are usually plentiful and "negotiable" and you can hire them for an extended period of time.
If you like shopping there is a mall called Times Square and for a real local experience there is the Craft Market closer to Negril village but be aware the vendors are aggressive and relentless, and largely sell the same stuff. However, there are a few real artisans there who sell their own handmade crafts like carvings.
The most popular tourist destination in Negril is probably Rick's Cafe in the west end. Sunset is the most popular time and there are also cliff divers (tourists can also do this) and a band...expensive but a must do at least once. There is also Margarittaville on Seven Mile beach which is fun and quirky.
On our last trip 4 of us took a taxi to some real Jamaican bars in Negril, very inexpensive and found the local people to be very friendly and eager to share their culture.

John