DTD is free. It is just a shopping area with a bunch of restaurants. DisneyQuest is located there, you can use one of your "plus" options for that. Cirque D' Soleil (or however you spell it!) is also there and that is a separate admission but not a 'Plus" option. Go and enjoy. We went several times last week on our trip! BEWARE......The World of Disney Store is ALWAYS a MADHOUSE!!!!!!
I'm not sure how "free" it really is. For some reason every time we go, we are mysteroiusly parted with more of our money. Generally more than a days admission is. Must be some strange magnetic force that turns money into gifts. As for needing a ticket though, only Pleasure Island has admission prices into their clubs.