You can get the dining plan, but I doubt it would be worth it. I have Florida Resident seasonal passes, and to get the dining plan this trip I had to get a package with a one day regular ticket for each person in the room and on the plan. I was then aloud to add dining. It was fine with me, since I didn't know the dining plan had changed as of 2008. Once I found out there had been changes to the plan, it was actually more expenssive for me to be on the plan. I could have gotten a better deal on room rates and not had to pay for the unneeded ticket, but it was to late for me to cancel.
I would say depending on when you are going, add up the cost of a room at the passholder rate, and then go to allears.net and look at the menus of the places you plan to eat. Add up what you would order, and then see if it is a deal for you to purchase a package with one day ticket and dining or not. Hope this helps.