There are lots of little details in the WWoHP to take in. Now Im certainly a "hardcore" Potter fan and although I have visited the park several times, Im sure there are still things I missed.
As for little things only fans of the books might notice, I'm not so sure. However, the best part for this nerd fan was just to look at all the little displays. The bottles of Firewhiskey and Pickled Poxie Eggs on the sheleves behind the bar at the Hogshead. The school trunks displayed in Filches(such as Neville's with his 100 uses of water plants book peeking out of it), in the Gryffindor Common room at FJ, the cork board with signs such as "wizard chest practice with Hufflepuff-8pm Great Hall". My favorite part was reading the signs on the registers ect in the stores and Hogshead/Three Broomsticks. Such as in Dervish and Banges the closing duties sign that included "Make sure cage is locked on the Monster book of Monsters-we know what happened last time" and "When clear of customers, turn off lights and use security spell before leaving". There are also of course things like the bottle of Skele-grow, and the old copy of the Daily Prophet sticking out of one the student trunks in Filches. Plus, the little effects such as the shadows on the walls of the Three Broomsticks, and the sounds of doors opening and closing up stairs ect.
They really did an incredible job of tossing in so many little elements of detail to make the whole place feel like you really were in Hogwarts or Hogsmeade. Sure the big window displays and all that are straight out of the movies/books and they are done with such accuracy it's like really seeing what Harry saw that first time he walked into Honeydukes(I adored the Clippy's Clip Joint display very much). But the added little details like the signs of "no underage wizards are to be served alcohol" and Wizarding Wireless Network sign over by the Hogshead. Just so many little things that made it feel so real and not like a themepark. It was so well done and beyond what even this Potter nerd dreamed they would do.
