If you want to do a day trip I'd highly recommend the Appleton Rum Factory tour. If you leave early, take the tour and then send an afternoon at YS Falls. Appletons has done a full renovation a few years back but I find the best part to be the drive there and of course the rum tasting helps.

For your safe reliable driver check out the transportation section on Negril.com. Prices have gone up though so expect that.