We did a day trip day trip to Kingston last February. It was a long day, leaving Negril about 6am and returning about 8pm. It was worth it. Never felt threatened or unsafe, but then again we didn't go running through Tivoli Gardens either. We went to Trenchtown, the National Stadium and out to Port Royal. The highlight of the trip was the Bob Marley House on Hope Road. If you are a fan at all it is a must. Wouldn't do it every trip, but I'm damned glad we did it.