It really depends on what you are planning to shoot. The 18-55 will work ok in many situations, but once you get into low light, moving situations it may struggle. With a tripod, it will handle fireworks. If you are planning on shooting the safari ride I would recommend a longer reach. A longer reach is also sometimes necessary if you want closeups of the characters in the outside shows. If you plan to shoot the lowlight parades without flash then I would recommend a lens with f2.8 or larger aperture. Its going to be totally up to you what you will need. The dark rides are another story and will require a fast lens. Stick to what you want to shoot, get the proper equipment, try to stay within your equipment's limitations and you won't be disappointed.