Hi Mama. I've been to Disney a couple of times, but never on a cruise. I hear the Disney Cruise is wonderful, but pricey. Everything Disney is expensive though.
There are four different parks in Disney -- Epcot, Magic Kingdom, Animal Kingdom, and MGM Studios. I would recommend reading http://disneyworld.disney.go.com/planning-guides/in-depth... here to get some information.
Also, October is a great time in Orlando! The weather is great and the parks are not that busy. Keep in mind that it is still hurricane season (until mid November). Also, the rainy season means that you will likely get a short rainfall each day. But, it dries up quickly.
I highly recommend a character breakfast or dinner. They can be expensive, but it will give your child the opportunity to meet many characters at one time. It can be exhausting and stressful to wait in many lines to meet different characters. Many of the character meals fill up quickly and in advance, so you will want to make a reservation. http://disneyworld.disney.go.com/restaurants/?sortBy=nG:h...
I would buy your tickets right on the Disney website or at the park. Do not be fooled by people offering free tickets. This is only if you attend a very long sales presentation where they try to sell you a timeshare. NOT FUN!!! I know from personal experience. If you buy them at the park, it can be a pain because there can be long lines. There are several different options for tickets depending on what you are looking to do.
I hope some of that helps!