The best way to do it is to get a good map --the one sold at any EssoStation is the best-- and ask a lot of questions. [NOTE: Not all nameslisted below are marked along the road.] 

When you leave out of the airport enter the round-about. Take the 3rd left exit out of the round-about and continue to the end of the road. At the Ttake a left. This will put you on the 'Hip Strip' of Montego Bay whereyou will pass lots of duty free shops, restaurants, hotels, etc.

Continue straight on this road until you come to the first set of lights. At this set of lights, take a right passing by Kentucky Fried Chicken.

Continue on this road straight through three more sets of lights. At the 4th set of lights take a left. 

Continue to the end of this road passing a large shopping center on the right and take a right at theend of the road.
You are now leaving out of Montego Bay. 

Drive until the second set of lights and take a left up the hilltowards Anchovy. Then on to Ramble.
As you pass a large orange grove on the right you will go over a bridge and come to a road to the left.
STAY TO THE RIGHT heading towards Savannah La Mar. Do not head to Bethel Town.

Continue on through Haddo and on into Whithorn. In Whithorn you want to take a right heading towards Ferris Cross. You will go down a good sized hill with a beautiful view of sugar cane fields on the right. At the bottom of the hill stay straight and do not take the right. 

Continue on until you come to a T in the road in Ferris Cross and take a left heading towards Black River.

Continue on through Belmont, Whitehouse, and into the Parish of St. Elizabeth. 

At the round-about stay to your right heading towards Black River.

Once in Black River take a left at the one-way street and then take the first right. You will wind past the market. Stay to the
right and eventually come to another T. Take the left and go over the bridge. 

Take your third right at the Jack Sprat restaurant sign which will be about 3 - 4 miles out of town and from there the signs are good directing you to Treasure Beach.

The trick is stop and ask a lot of questions, and when asking, ask for directions to the next town on the map. Many people do not drive and may not know how to get to Treasure Beach but will know how to get to the next town.