Welcome Kathy, Dave, Benjamin and Spencer to the Sept. 15th cruise. You've got some great company going with you for the four days. Kathy, I am assuming by your post you haven't had time to take a swing through the DIS board. Hope you can get a look at some of the great ideas other cruisers have come up with to make your four days just fantastic.
You already indicated when you made your reservation whether you wanted early or late seating. When you check in, you will be notified of what your dinner rotation is. Are you doing the land portion first then coming over? If so, where will you be at WDW?
You can bring soda and beer on board. Lots of discussions on that particular subject on the cruise board. Suffice it to say, it's all personal preference. My DW and I will not be packing it on board, but we will be making full use of the mugs, especially the ESPN beer mugs (that's for me, the DW is a Pepsi fanatic).
Be sure to get out and look at Barb's (Inkognito) and Dave's (Dave from Marrietta) sites. I don't have the links here, but you'll find them all over the Cruise board threads. These are sources of invaluable information to help you plan your trip. By the way, when do you leave? Some time next week I'll try to pull a complete list together, as short as it is. We figure we are going to have an empty ship and lots of attentive CMs at our beck and call.