Keep in mind that the Jamaican people tend to have a great sense of humor. Treat the pushy vendors with a bit of courtesy and humor and things will be a tad smoother. I once had a drug dealer really getting pushy with me. I was lying on the beach...not on a cruise, but a 9 day vacation in Ochos Rios. He told me that Mick Jagger bought drugs from him and I replied that Mick Jagger could afford lawyers. He laughed and moved on....finally.
But, shirlee, as much as I love Jamaica, it is NOT a place to get off the beaten path on your own. That is an invitation to crime in Jamaica, as it would be in parts of the US. But, certain Caribbean ports have higher crime rates than others and this one is very high. Not the highest, that honor belongs to Martinique (one of my favorites), but having spent quite a bit of time in Jamaica over many years, I would be more cautious there than most places. Enjoy it...but safely!