See if you can rent one, and try it out during evening hours, or at night. See what it will do, if it can take the kind of pictures you're looking for. I'm not familiar enough with that model to know but I'd suggest something with manual control of the exposure (point-and-shoot cameras are more limited in what you can do with them). The lens sounds like you can get a lot done with it, and my 18-55mm is the lens I use most often. It's a very good general lens. Another one to consider is 55-200mm; it's a lot of zoom and can be helpful for things that you can't walk up to to get closer for those close-up shots.
For dark rides, I'd suggest you think about getting or renting a 35mm or 50mm f/1.4 - you get a lot more options for low-light photos. Read hotsauce1's photo thread- he has a lot of seriously good information. You can practice taking pictures of neon maybe in your local downtown, and any subject you like will work for sunset/dark/evening practice shots.
The other thing I'd suggest is using your camera a lot before your trip- know how to change the settings, get an idea what you'll need to put shutter speed and f/stop at, and what it does. Read a book on photography (my personal favorite author is Bryan Peterson; he's got one that's a general guide to photos that's pretty good). Find a flowerbed or something, and take as many photos with as many different settings as you can possibly think of. See what it all comes out like.
And have a good time!
Another toy photo...
I love the toy photo!! So cute!
My 6-year-old son, in awe of the Iron Man exhibit at Innoventions.
This makes me wish Tomorrowland had higher structures.
A picture like you just posted is exactly what I'm looking for, I want to take crisp and clean looking pictures. I'm willing to get a camera that doesn't just do all the work for me, I'm willing to learn how the camera works and becoming a lot more familiar with it. I have a Costco giftcard and after watching video samples and picture samples I do plan on buying this package deal! Let me know what you think
Canon T4i DSLR Camera 2 Lens Bundle