Playing a game suited for table-top (like D&D) when people are scattered and/or waiting in line might be unneedlessly difficult. You might be better off playing D&D themed games.
(I don't know the DisneyLAND rides, so I'm using DisneyWorld rides as examples) Perhaps something like: After riding the SnowWhite ride, all of you try and figure out the character sheets for the witch, snow white, and the dwarves. Best done in 3.5e or whatever edition the group is most familiar with already since you won't be able to easily have books there... Do this while you're waiting in line at the next ride to pass the time. Then after the next ride do the stats for the characters seen in that ride, and so on.
Coming up with the character sheets could be:
* individual: everyone come up with their own character sheets and we compare later tonight. Though if you won't have paper/pencil to write the ideas down, then this isn't a great option.
*in teams: this may work especially well if everyone will be 'scattered' in roughly the same groupings the whole time. and then compare later on (maybe during lunch breaks together or such. it would encourage some cooperation and a little competition.
* or entirely group done: this would be based entirely on cooperation with no competition. Though it may fall short if you have quiet people that will get shut out or if there are too many of you for everyone to actively participate (i.e. 10 people in a line, the main converation would be focused around the most vocal while the people further away from that vocal center would have less input due to outside noise and distractions)
There would, of course, be no right or wrong answer, but it would get them thinking and be both D&D and Disney based.
Obviously, this works best for rides that have -character- based themes... you'll be hard pressed to do the same for say space mountain. But maybe for something like the Haunted Mansion, it isn't character sheets but instead 'develop the background story as to how this place came about -- why are so many ghosts focused here, paying attention to period of dress and decoration, etc"
For the rides that aren't character based or wouldn't fit at all in to a D&D type setting (like space mountain) have a couple reserve Disney characters that aren't on the rides. For instance, the cast from incredibles, or little mermaid - just a couple backup ideas that won't have a ride for when you don't have a D&D theme available while waiting.
Again, they should do this _after_ riding the ride, while waiting in line for the next ride -- why? the ride will put them in 'the zone' and give them the character/setting feel.
Oh, and have point buy or prerolled ability score arrays (18, 16, 16, 12, 10, 8 -- whatever), that way everyone (if individual) or the teams (if in teams) will have equal footing to start from.
My thoughts are scattered, apologies for that, but hopefully you can figure out where i'm going with all these rambles.
