Used Rally from Rally Tours (876) 845-2307 / 776-5591. Superb taxi driver, looked after us our entire 7 day stay in Jamaica, went above and beyond to make our trip especially memorable. Give him a call, you won't be sorry. Rio Grande was a long drive from Montego Bay, not sure how it compares to the Martha Brae rafting but the drive was very scenic. Cost is $72 to take 2 people on a bamboo raft up river, they stop a couple of times to swim in the beautiful clear water. Very quiet, secluded spot, we were the only people there which is what we wanted. No food, drink for purchase, no change rooms or bathrooms, just local habitat. Afterwards we went to Boston Jerk Centre, best jerk we had on our visit, totally local and authentic, superb.