Ah. Sorry, I don't play that game so I wasn't thinking in those terms.
That's a hard one as I don't really care much about the design of those rides, but at least for the scramblers I can think of something like a hanging teacups - perhaps hanging lanterns or something. I hate how you have that huge framework above teh cars. For the tilt-a-whirl you could always have something with an asian theme, and decorate the ride structure like an oriental garden. I am not sure how much themeing you can do in RCT2.
Oh, the Scrambler is a classic flat ride - there are many different versions and names, actually, but the idea is that you have three groups of three ride vehicles. The cars are basically seats with a lap-bar in front of you. Each group is arranged in a circle, with the cars facing forwards. Each group is then hung from an overhead support which goes to the center. As the cupport rotates, the groups on the end of the support also rotate, but in the opposite direction, so that you go spinning around a central point. The centrifigal (sp?) force pushes you to the outside of the car when you reach the outside. If you have ever been to a carnival you have seen one, I am sure.