It really depends on how you book your cruise. We've always booked our cruises separately from our WDW leg. By booking each leg separately you can stay in whatever category room you want on the ship, if you book a land/sea pkg the ship category is determined by the type of room you have at WDW.
No matter how you book, there are a variety of ways to get from Port Canaveral to WDW. There is the Disney bus, we've never done this but many do. We always get a town car. It's about the same price as the Disney bus but we can be picked up when we want and they will stop at a grocery store on the way to the ship. We enjoy the extra pampering of the town car service. You could also rent a car. Many do this also. If you go to the cruise message board you will find alot of information on this.
