I think you could easily use cards that have different backs, like the Dungeon, City, Timescape, ect. cards. Adventure cards would be harder, but if you could just make a dungeon door card, then the rest probably wouldn't be necessary. Or you could just not use the 4th ed. adventure cards and use the old one with 4th addition purchase cards, characters, spells, and board.Yeah this would work. Some folks just put the cards into protective sleeves that are opaque. So does not mater if they are a diff card you cant tell what is in there.