There are some behind the scenes stuff you can do too, if you pay a premium for it early, or rush in at park opening to be the first of 20 or so.
At Disneyland, there was some Club 33 or something like that, which got you a pricey dinner on a balcony looking out over the fireworks display. We enjoyed that.
The next day I was threatened with divorce.
There are some tunnel, backstage tours too.
One interesting thing about Disneyworld is that, given its swampy locale, the whole "ground level" is actually the equivalent of a second story building with all the tunnels, facilities, character dressing rooms, etc., networked throughout the "first floor" underground of each park.