Forget it. Its just not worth shleping all the gear to negril for one or two random days. I just came back from a three week stay in negril. 95% of the time winds are off shore. Occasionally you get a side shore north wind. One day we had a freak SW wind at about 12-15 which was perfect but now you have the launch and land issue. Beach is very narrow and crowded. You're best bet for this would be by Cosmo beach next to Beaches if the owner doesn't get all bent you're on his beach which happened to me just flying a large foil one day. He shewed me away off his beach. If you do get lucky with an onshore or side shore wind you better be pumped up and ready to go cause in a heart beat this can just die and go off shore. As far as waves, nada. If you get anything they are powerless windswell with no push. So as far as surfing or kiteboarding this is not the spot. Like you said Falmouth and Ocho Rios are probably better for this but that's a day trip from negril. On the other hand you are in SUP heaven. The water is calm and clear and you can SUP the entire seven mile beach. Rentals are available at the Tree House and if you want to do it everyday you could probably work something out with Gail, the owner. She is a SUP enthusiast.