This was helpful for me, so I thought I would pass it along.

I found a good road map for the whole island here:
http://www.jamaicancaves.org/jamaica-road-map.htm

And one on just TB:
http://www.jamaicancaves.org/map_treasure_beach.htm

Another good resource: International Travel Maps/ITMB out of Vancouver has just reissued
its map of Jamaica, arguably the best, now printed on a Tyvek-like
waterproof stock so multiple foldings won't result in a map in tatters. Full island map.
Close-up maps of MoBay,
Ochie, Porty, Mandeville, Spanish Town and one
full side a close-up of Kingston. St.Bess is
decently covered, tho the back road from Fort
Charles to Black River, for example, is not
shown. About US$10.95
http://www.itmb.com

Those are good links, but keep in mind the TB map doesn't have a legend on it saying that the 'road' linking Great Bay to Calabash Bay (just above the Great Pedro Pond) is not the best to drive on, which may be an understatement.