shouldn't be hard at all. Tourist areas in the islands, mexico and central and south america there are usually people there to sell to ya. Like, in a resort there most likely won't be anyone but if ya go into town and stuff shouldn't be that hard to find. Might be easier for msyelf having dreadlocks, most poeple have no problem coming up to me if they got the herb. maybe wear a marijuana leaf t shirt or something... gl and enjoy your vacation

edit: one thing ya should watch out for is people trying to rip ya off, don't be afraid to haggle on the price they will most likely go down in price if you protest their price, they just start high and sell low