If I were staying in Treasure Beach, then I might consider a South Coast Tour Operator but staying in Negril? It would be an "arm and a leg" to have someone drive up from there; take you back there and then bring you back to Negril!
I think Talk of the Town Tours is a good alternative and a great company as well.
Jamaica abounds with Red Plate, licensed taxis with drivers and/or owners who would love to take you on a trip for more money than they could make in a day beating their vehicle to death on a Route Run. I know everyone wants to have something "nailed down" before they get to Jamaica but this is a country that runs on bargaining. You could get a good price by just asking around once you get there (as an option).
Peace and Guidance